deps: import acorn@5.2.1

Imported from the tarball published on npm
(https://registry.npmjs.org/acorn/-/acorn-5.2.1.tgz).

PR-URL: https://github.com/nodejs/node/pull/15566
Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

13 files changed, 12158 insertions, 0 deletions

diff --git a/deps/acorn/AUTHORS b/deps/acorn/AUTHORS
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+List of Acorn contributors. Updated before every release.
+
+Adrian Rakovsky
+Alistair Braidwood
+Amila Welihinda
+Andres Suarez
+Angelo
+Aparajita Fishman
+Arian Stolwijk
+Artem Govorov
+Bradley Heinz
+Brandon Mills
+Charles Hughes
+Conrad Irwin
+Daniel Tschinder
+David Bonnet
+Domenico Matteo
+ehmicky
+Forbes Lindesay
+Gilad Peleg
+impinball
+Ingvar Stepanyan
+Jackson Ray Hamilton
+Jesse McCarthy
+Jiaxing Wang
+Joel Kemp
+Johannes Herr
+John-David Dalton
+Jordan Klassen
+Jürg Lehni
+Kai Cataldo
+keeyipchan
+Keheliya Gallaba
+Kevin Irish
+Kevin Kwok
+krator
+Marek
+Marijn Haverbeke
+Martin Carlberg
+Mat Garcia
+Mathias Bynens
+Mathieu 'p01' Henri
+Matthew Bastien
+Max Schaefer
+Max Zerzouri
+Mihai Bazon
+Mike Rennie
+naoh
+Nicholas C. Zakas
+Nick Fitzgerald
+Olivier Thomann
+Oskar Schöldström
+Paul Harper
+Peter Rust
+PlNG
+Prayag Verma
+ReadmeCritic
+r-e-d
+Richard Gibson
+Rich Harris
+Sebastian McKenzie
+Shahar Soel
+Simen Bekkhus
+Teddy Katz
+Timothy Gu
+Toru Nagashima
+Victor Homyakov
+Wexpo Lyu
+zsjforcn
diff --git a/deps/acorn/CHANGELOG.md b/deps/acorn/CHANGELOG.md
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+## 5.2.1 (2017-10-30)
+
+### Bug fixes
+
+Fix a token context corruption bug.
+
+## 5.2.0 (2017-10-30)
+
+### Bug fixes
+
+Fix token context tracking for `class` and `function` in property-name position.
+
+Make sure `%*` isn't parsed as a valid operator.
+
+The `full` and `fullAncestor` walkers no longer visit nodes multiple times.
+
+Allow shorthand properties `get` and `set` to be followed by default values.
+
+Disallow `super` when not in callee or object position.
+
+### New features
+
+Support [`directive` property](https://github.com/estree/estree/compare/b3de58c9997504d6fba04b72f76e6dd1619ee4eb...1da8e603237144f44710360f8feb7a9977e905e0) on directive expression statements.
+
+## 5.1.2 (2017-09-04)
+
+### Bug fixes
+
+Disable parsing of legacy HTML-style comments in modules.
+
+Fix parsing of async methods whose names are keywords.
+
+## 5.1.1 (2017-07-06)
+
+### Bug fixes
+
+Fix problem with disambiguating regexp and division after a class.
+
+## 5.1.0 (2017-07-05)
+
+### Bug fixes
+
+Fix tokenizing of regexps in an object-desctructuring `for`/`of` loop and after `yield`.
+
+Parse zero-prefixed numbers with non-octal digits as decimal.
+
+Allow object/array patterns in rest parameters.
+
+Don't error when `yield` is used as a property name.
+
+Allow `async` as a shorthand object property.
+
+Make the ES module version of the loose parser actually work.
+
+### New features
+
+Implement the [template literal revision proposal](https://github.com/tc39/proposal-template-literal-revision) for ES9.
+
+New walker functions `full` and `fullAncestor`.
+
+## 5.0.3 (2017-04-01)
+
+### Bug fixes
+
+Fix spurious duplicate variable definition errors for named functions.
+
+## 5.0.2 (2017-03-30)
+
+### Bug fixes
+
+A binary operator after a parenthesized arrow expression is no longer incorrectly treated as an error.
+
+## 5.0.0 (2017-03-28)
+
+### Bug fixes
+
+Raise an error for duplicated lexical bindings.
+
+Fix spurious error when an assignement expression occurred after a spread expression.
+
+Accept regular expressions after `of` (in `for`/`of`), `yield` (in a generator), and braced arrow functions.
+
+Allow labels in front or `var` declarations, even in strict mode.
+
+### Breaking changes
+
+Parse declarations following `export default` as declaration nodes, not expressions. This means that class and function declarations nodes can now have `null` as their `id`.
+
+## 4.0.11 (2017-02-07)
+
+### Bug fixes
+
+Allow all forms of member expressions to be parenthesized as lvalue.
+
+## 4.0.10 (2017-02-07)
+
+### Bug fixes
+
+Don't expect semicolons after default-exported functions or classes,
+even when they are expressions.
+
+Check for use of `'use strict'` directives in non-simple parameter
+functions, even when already in strict mode.
+
+## 4.0.9 (2017-02-06)
+
+### Bug fixes
+
+Fix incorrect error raised for parenthesized simple assignment
+targets, so that `(x) = 1` parses again.
+
+## 4.0.8 (2017-02-03)
+
+### Bug fixes
+
+Solve spurious parenthesized pattern errors by temporarily erring on
+the side of accepting programs that our delayed errors don't handle
+correctly yet.
+
+## 4.0.7 (2017-02-02)
+
+### Bug fixes
+
+Accept invalidly rejected code like `(x).y = 2` again.
+
+Don't raise an error when a function _inside_ strict code has a
+non-simple parameter list.
+
+## 4.0.6 (2017-02-02)
+
+### Bug fixes
+
+Fix exponential behavior (manifesting itself as a complete hang for
+even relatively small source files) introduced by the new 'use strict'
+check.
+
+## 4.0.5 (2017-02-02)
+
+### Bug fixes
+
+Disallow parenthesized pattern expressions.
+
+Allow keywords as export names.
+
+Don't allow the `async` keyword to be parenthesized.
+
+Properly raise an error when a keyword contains a character escape.
+
+Allow `"use strict"` to appear after other string literal expressions.
+
+Disallow labeled declarations.
+
+## 4.0.4 (2016-12-19)
+
+### Bug fixes
+
+Fix issue with loading acorn_loose.js with an AMD loader.
+
+Fix crash when `export` was followed by a keyword that can't be
+exported.
+
+## 4.0.3 (2016-08-16)
+
+### Bug fixes
+
+Allow regular function declarations inside single-statement `if`
+branches in loose mode. Forbid them entirely in strict mode.
+
+Properly parse properties named `async` in ES2017 mode.
+
+Fix bug where reserved words were broken in ES2017 mode.
+
+## 4.0.2 (2016-08-11)
+
+### Bug fixes
+
+Don't ignore period or 'e' characters after octal numbers.
+
+Fix broken parsing for call expressions in default parameter values
+of arrow functions.
+
+## 4.0.1 (2016-08-08)
+
+### Bug fixes
+
+Fix false positives in duplicated export name errors.
+
+## 4.0.0 (2016-08-07)
+
+### Breaking changes
+
+The default `ecmaVersion` option value is now 7.
+
+A number of internal method signatures changed, so plugins might need
+to be updated.
+
+### Bug fixes
+
+The parser now raises errors on duplicated export names.
+
+`arguments` and `eval` can now be used in shorthand properties.
+
+Duplicate parameter names in non-simple argument lists now always
+produce an error.
+
+### New features
+
+The `ecmaVersion` option now also accepts year-style version numbers
+(2015, etc).
+
+Support for `async`/`await` syntax when `ecmaVersion` is >= 8.
+
+Support for trailing commas in call expressions when `ecmaVersion`
+is >= 8.
+
+## 3.3.0 (2016-07-25)
+
+### Bug fixes
+
+Fix bug in tokenizing of regexp operator after a function declaration.
+
+Fix parser crash when parsing an array pattern with a hole.
+
+### New features
+
+Implement check against complex argument lists in functions that
+enable strict mode in ES7.
+
+## 3.2.0 (2016-06-07)
+
+### Bug fixes
+
+Improve handling of lack of unicode regexp support in host
+environment.
+
+Properly reject shorthand properties whose name is a keyword.
+
+Don't crash when the loose parser is called without options object.
+
+### New features
+
+Visitors created with `visit.make` now have their base as _prototype_,
+rather than copying properties into a fresh object.
+
+Make it possible to use `visit.ancestor` with a walk state.
+
+## 3.1.0 (2016-04-18)
+
+### Bug fixes
+
+Fix issue where the loose parser created invalid TemplateElement nodes
+for unclosed template literals.
+
+Properly tokenize the division operator directly after a function
+expression.
+
+Allow trailing comma in destructuring arrays.
+
+### New features
+
+The walker now allows defining handlers for `CatchClause` nodes.
+
+## 3.0.4 (2016-02-25)
+
+### Fixes
+
+Allow update expressions as left-hand-side of the ES7 exponential
+operator.
+
+## 3.0.2 (2016-02-10)
+
+### Fixes
+
+Fix bug that accidentally made `undefined` a reserved word when
+parsing ES7.
+
+## 3.0.0 (2016-02-10)
+
+### Breaking changes
+
+The default value of the `ecmaVersion` option is now 6 (used to be 5).
+
+Support for comprehension syntax (which was dropped from the draft
+spec) has been removed.
+
+### Fixes
+
+`let` and `yield` are now “contextual keywords”, meaning you can
+mostly use them as identifiers in ES5 non-strict code.
+
+A parenthesized class or function expression after `export default` is
+now parsed correctly.
+
+### New features
+
+When `ecmaVersion` is set to 7, Acorn will parse the exponentiation
+operator (`**`).
+
+The identifier character ranges are now based on Unicode 8.0.0.
+
+Plugins can now override the `raiseRecoverable` method to override the
+way non-critical errors are handled.
+
+## 2.7.0 (2016-01-04)
+
+### Fixes
+
+Stop allowing rest parameters in setters.
+
+Make sure the loose parser always attaches a `local` property to
+`ImportNamespaceSpecifier` nodes.
+
+Disallow `y` rexexp flag in ES5.
+
+Disallow `\00` and `\000` escapes in strict mode.
+
+Raise an error when an import name is a reserved word.
+
+## 2.6.4 (2015-11-12)
+
+### Fixes
+
+Fix crash in loose parser when parsing invalid object pattern.
+
+### New features
+
+Support plugins in the loose parser.
+
+## 2.6.2 (2015-11-10)
+
+### Fixes
+
+Don't crash when no options object is passed.
+
+## 2.6.0 (2015-11-09)
+
+### Fixes
+
+Add `await` as a reserved word in module sources.
+
+Disallow `yield` in a parameter default value for a generator.
+
+Forbid using a comma after a rest pattern in an array destructuring.
+
+### New features
+
+Support parsing stdin in command-line tool.
+
+## 2.5.2 (2015-10-27)
+
+### Fixes
+
+Fix bug where the walker walked an exported `let` statement as an
+expression.
+
+## 2.5.0 (2015-10-27)
+
+### Fixes
+
+Fix tokenizer support in the command-line tool.
+
+In the loose parser, don't allow non-string-literals as import
+sources.
+
+Stop allowing `new.target` outside of functions.
+
+Remove legacy `guard` and `guardedHandler` properties from try nodes.
+
+Stop allowing multiple `__proto__` properties on an object literal in
+strict mode.
+
+Don't allow rest parameters to be non-identifier patterns.
+
+Check for duplicate paramter names in arrow functions.
diff --git a/deps/acorn/LICENSE b/deps/acorn/LICENSE
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+++ b/deps/acorn/LICENSE
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+Copyright (C) 2012-2017 by various contributors (see AUTHORS)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/deps/acorn/README.md b/deps/acorn/README.md
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+# Acorn
+
+[![Build Status](https://travis-ci.org/ternjs/acorn.svg?branch=master)](https://travis-ci.org/ternjs/acorn)
+[![NPM version](https://img.shields.io/npm/v/acorn.svg)](https://www.npmjs.com/package/acorn)
+[![CDNJS](https://img.shields.io/cdnjs/v/acorn.svg)](https://cdnjs.com/libraries/acorn)  
+[Author funding status: ![maintainer happiness](https://marijnhaverbeke.nl/fund/status_s.png?force)](https://marijnhaverbeke.nl/fund/)
+
+A tiny, fast JavaScript parser, written completely in JavaScript.
+
+## Community
+
+Acorn is open source software released under an
+[MIT license](https://github.com/ternjs/acorn/blob/master/LICENSE).
+
+You are welcome to
+[report bugs](https://github.com/ternjs/acorn/issues) or create pull
+requests on [github](https://github.com/ternjs/acorn). For questions
+and discussion, please use the
+[Tern discussion forum](https://discuss.ternjs.net).
+
+## Installation
+
+The easiest way to install acorn is with [`npm`][npm].
+
+[npm]: https://www.npmjs.com/
+
+```sh
+npm install acorn
+```
+
+Alternately, download the source.
+
+```sh
+git clone https://github.com/ternjs/acorn.git
+```
+
+## Components
+
+When run in a CommonJS (node.js) or AMD environment, exported values
+appear in the interfaces exposed by the individual files, as usual.
+When loaded in the browser (Acorn works in any JS-enabled browser more
+recent than IE5) without any kind of module management, a single
+global object `acorn` will be defined, and all the exported properties
+will be added to that.
+
+### Main parser
+
+This is implemented in `dist/acorn.js`, and is what you get when you
+`require("acorn")` in node.js.
+
+**parse**`(input, options)` is used to parse a JavaScript program.
+The `input` parameter is a string, `options` can be undefined or an
+object setting some of the options listed below. The return value will
+be an abstract syntax tree object as specified by the
+[ESTree spec][estree].
+
+When  encountering   a  syntax   error,  the   parser  will   raise  a
+`SyntaxError` object with a meaningful  message. The error object will
+have a `pos` property that indicates the character offset at which the
+error occurred,  and a `loc`  object that contains a  `{line, column}`
+object referring to that same position.
+
+[estree]: https://github.com/estree/estree
+
+- **ecmaVersion**: Indicates the ECMAScript version to parse. Must be
+  either 3, 5, 6 (2015), 7 (2016), 8 (2017), or 9 (2018, partial
+  support). This influences support for strict mode, the set of
+  reserved words, and support for new syntax features. Default is 7.
+
+  **NOTE**: Only 'stage 4' (finalized) ECMAScript features are being
+  implemented by Acorn.
+
+- **sourceType**: Indicate the mode the code should be parsed in. Can be
+  either `"script"` or `"module"`. This influences global strict mode
+  and parsing of `import` and `export` declarations.
+
+- **onInsertedSemicolon**: If given a callback, that callback will be
+  called whenever a missing semicolon is inserted by the parser. The
+  callback will be given the character offset of the point where the
+  semicolon is inserted as argument, and if `locations` is on, also a
+  `{line, column}` object representing this position.
+
+- **onTrailingComma**: Like `onInsertedSemicolon`, but for trailing
+  commas.
+
+- **allowReserved**: If `false`, using a reserved word will generate
+  an error. Defaults to `true` for `ecmaVersion` 3, `false` for higher
+  versions. When given the value `"never"`, reserved words and
+  keywords can also not be used as property names (as in Internet
+  Explorer's old parser).
+
+- **allowReturnOutsideFunction**: By default, a return statement at
+  the top level raises an error. Set this to `true` to accept such
+  code.
+
+- **allowImportExportEverywhere**: By default, `import` and `export`
+  declarations can only appear at a program's top level. Setting this
+  option to `true` allows them anywhere where a statement is allowed.
+
+- **allowHashBang**: When this is enabled (off by default), if the
+  code starts with the characters `#!` (as in a shellscript), the
+  first line will be treated as a comment.
+
+- **locations**: When `true`, each node has a `loc` object attached
+  with `start` and `end` subobjects, each of which contains the
+  one-based line and zero-based column numbers in `{line, column}`
+  form. Default is `false`.
+
+- **onToken**: If a function is passed for this option, each found
+  token will be passed in same format as tokens returned from
+  `tokenizer().getToken()`.
+
+  If array is passed, each found token is pushed to it.
+
+  Note that you are not allowed to call the parser from the
+  callback—that will corrupt its internal state.
+
+- **onComment**: If a function is passed for this option, whenever a
+  comment is encountered the function will be called with the
+  following parameters:
+
+  - `block`: `true` if the comment is a block comment, false if it
+    is a line comment.
+  - `text`: The content of the comment.
+  - `start`: Character offset of the start of the comment.
+  - `end`: Character offset of the end of the comment.
+
+  When the `locations` options is on, the `{line, column}` locations
+  of the comment’s start and end are passed as two additional
+  parameters.
+
+  If array is passed for this option, each found comment is pushed
+  to it as object in Esprima format:
+
+  ```javascript
+  {
+    "type": "Line" | "Block",
+    "value": "comment text",
+    "start": Number,
+    "end": Number,
+    // If `locations` option is on:
+    "loc": {
+      "start": {line: Number, column: Number}
+      "end": {line: Number, column: Number}
+    },
+    // If `ranges` option is on:
+    "range": [Number, Number]
+  }
+  ```
+
+  Note that you are not allowed to call the parser from the
+  callback—that will corrupt its internal state.
+
+- **ranges**: Nodes have their start and end characters offsets
+  recorded in `start` and `end` properties (directly on the node,
+  rather than the `loc` object, which holds line/column data. To also
+  add a [semi-standardized][range] `range` property holding a
+  `[start, end]` array with the same numbers, set the `ranges` option
+  to `true`.
+
+- **program**: It is possible to parse multiple files into a single
+  AST by passing the tree produced by parsing the first file as the
+  `program` option in subsequent parses. This will add the toplevel
+  forms of the parsed file to the "Program" (top) node of an existing
+  parse tree.
+
+- **sourceFile**: When the `locations` option is `true`, you can pass
+  this option to add a `source` attribute in every node’s `loc`
+  object. Note that the contents of this option are not examined or
+  processed in any way; you are free to use whatever format you
+  choose.
+
+- **directSourceFile**: Like `sourceFile`, but a `sourceFile` property
+  will be added (regardless of the `location` option) directly to the
+  nodes, rather than the `loc` object.
+
+- **preserveParens**: If this option is `true`, parenthesized expressions
+  are represented by (non-standard) `ParenthesizedExpression` nodes
+  that have a single `expression` property containing the expression
+  inside parentheses.
+
+[range]: https://bugzilla.mozilla.org/show_bug.cgi?id=745678
+
+**parseExpressionAt**`(input, offset, options)` will parse a single
+expression in a string, and return its AST. It will not complain if
+there is more of the string left after the expression.
+
+**getLineInfo**`(input, offset)` can be used to get a `{line,
+column}` object for a given program string and character offset.
+
+**tokenizer**`(input, options)` returns an object with a `getToken`
+method that can be called repeatedly to get the next token, a `{start,
+end, type, value}` object (with added `loc` property when the
+`locations` option is enabled and `range` property when the `ranges`
+option is enabled). When the token's type is `tokTypes.eof`, you
+should stop calling the method, since it will keep returning that same
+token forever.
+
+In ES6 environment, returned result can be used as any other
+protocol-compliant iterable:
+
+```javascript
+for (let token of acorn.tokenizer(str)) {
+  // iterate over the tokens
+}
+
+// transform code to array of tokens:
+var tokens = [...acorn.tokenizer(str)];
+```
+
+**tokTypes** holds an object mapping names to the token type objects
+that end up in the `type` properties of tokens.
+
+#### Note on using with [Escodegen][escodegen]
+
+Escodegen supports generating comments from AST, attached in
+Esprima-specific format. In order to simulate same format in
+Acorn, consider following example:
+
+```javascript
+var comments = [], tokens = [];
+
+var ast = acorn.parse('var x = 42; // answer', {
+	// collect ranges for each node
+	ranges: true,
+	// collect comments in Esprima's format
+	onComment: comments,
+	// collect token ranges
+	onToken: tokens
+});
+
+// attach comments using collected information
+escodegen.attachComments(ast, comments, tokens);
+
+// generate code
+console.log(escodegen.generate(ast, {comment: true}));
+// > 'var x = 42;    // answer'
+```
+
+[escodegen]: https://github.com/estools/escodegen
+
+### dist/acorn_loose.js ###
+
+This file implements an error-tolerant parser. It exposes a single
+function. The loose parser is accessible in node.js via `require("acorn/dist/acorn_loose")`.
+
+**parse_dammit**`(input, options)` takes the same arguments and
+returns the same syntax tree as the `parse` function in `acorn.js`,
+but never raises an error, and will do its best to parse syntactically
+invalid code in as meaningful a way as it can. It'll insert identifier
+nodes with name `"✖"` as placeholders in places where it can't make
+sense of the input. Depends on `acorn.js`, because it uses the same
+tokenizer.
+
+### dist/walk.js ###
+
+Implements an abstract syntax tree walker. Will store its interface in
+`acorn.walk` when loaded without a module system.
+
+**simple**`(node, visitors, base, state)` does a 'simple' walk over
+a tree. `node` should be the AST node to walk, and `visitors` an
+object with properties whose names correspond to node types in the
+[ESTree spec][estree]. The properties should contain functions
+that will be called with the node object and, if applicable the state
+at that point. The last two arguments are optional. `base` is a walker
+algorithm, and `state` is a start state. The default walker will
+simply visit all statements and expressions and not produce a
+meaningful state. (An example of a use of state is to track scope at
+each point in the tree.)
+
+```js
+const acorn = require("acorn")
+const walk = require("acorn/dist/walk")
+
+walk.simple(acorn.parse("let x = 10"), {
+  Literal(node) {
+    console.log(`Found a literal: ${node.value}`)
+  }
+})
+```
+
+**ancestor**`(node, visitors, base, state)` does a 'simple' walk over
+a tree, building up an array of ancestor nodes (including the current node)
+and passing the array to the callbacks as a third parameter.
+
+```js
+const acorn = require("acorn")
+const walk = require("acorn/dist/walk")
+
+walk.ancestor(acorn.parse("foo('hi')"), {
+  Literal(_, ancestors) {
+    console.log("This literal's ancestors are:",
+                ancestors.map(n => n.type))
+  }
+})
+```
+
+**recursive**`(node, state, functions, base)` does a 'recursive'
+walk, where the walker functions are responsible for continuing the
+walk on the child nodes of their target node. `state` is the start
+state, and `functions` should contain an object that maps node types
+to walker functions. Such functions are called with `(node, state, c)`
+arguments, and can cause the walk to continue on a sub-node by calling
+the `c` argument on it with `(node, state)` arguments. The optional
+`base` argument provides the fallback walker functions for node types
+that aren't handled in the `functions` object. If not given, the
+default walkers will be used.
+
+**make**`(functions, base)` builds a new walker object by using the
+walker functions in `functions` and filling in the missing ones by
+taking defaults from `base`.
+
+**full**`(node, callback, base, state)` does a 'full'
+walk over a tree, calling the callback with the arguments (node, state, type)
+for each node
+
+**fullAncestor**`(node, callback, base, state)` does a 'full' walk over
+a tree, building up an array of ancestor nodes (including the current node)
+and passing the array to the callbacks as a third parameter.
+
+```js
+const acorn = require("acorn")
+const walk = require("acorn/dist/walk")
+
+walk.full(acorn.parse("1 + 1"), node => {
+  console.log(`There's a ${node.type} node at ${node.ch}`)
+})
+```
+
+**findNodeAt**`(node, start, end, test, base, state)` tries to
+locate a node in a tree at the given start and/or end offsets, which
+satisfies the predicate `test`. `start` and `end` can be either `null`
+(as wildcard) or a number. `test` may be a string (indicating a node
+type) or a function that takes `(nodeType, node)` arguments and
+returns a boolean indicating whether this node is interesting. `base`
+and `state` are optional, and can be used to specify a custom walker.
+Nodes are tested from inner to outer, so if two nodes match the
+boundaries, the inner one will be preferred.
+
+**findNodeAround**`(node, pos, test, base, state)` is a lot like
+`findNodeAt`, but will match any node that exists 'around' (spanning)
+the given position.
+
+**findNodeAfter**`(node, pos, test, base, state)` is similar to
+`findNodeAround`, but will match all nodes *after* the given position
+(testing outer nodes before inner nodes).
+
+## Command line interface
+
+The `bin/acorn` utility can be used to parse a file from the command
+line. It accepts as arguments its input file and the following
+options:
+
+- `--ecma3|--ecma5|--ecma6|--ecma7|--ecma8|--ecma9`: Sets the ECMAScript version
+  to parse. Default is version 7.
+
+- `--module`: Sets the parsing mode to `"module"`. Is set to `"script"` otherwise.
+
+- `--locations`: Attaches a "loc" object to each node with "start" and
+  "end" subobjects, each of which contains the one-based line and
+  zero-based column numbers in `{line, column}` form.
+
+- `--allow-hash-bang`: If the code starts with the characters #! (as in a shellscript), the first line will be treated as a comment.
+
+- `--compact`: No whitespace is used in the AST output.
+
+- `--silent`: Do not output the AST, just return the exit status.
+
+- `--help`: Print the usage information and quit.
+
+The utility spits out the syntax tree as JSON data.
+
+## Build system
+
+Acorn is written in ECMAScript 6, as a set of small modules, in the
+project's `src` directory, and compiled down to bigger ECMAScript 3
+files in `dist` using [Browserify](http://browserify.org) and
+[Babel](http://babeljs.io/). If you are already using Babel, you can
+consider including the modules directly.
+
+The command-line test runner (`npm test`) uses the ES6 modules. The
+browser-based test page (`test/index.html`) uses the compiled modules.
+The `bin/build-acorn.js` script builds the latter from the former.
+
+If you are working on Acorn, you'll probably want to try the code out
+directly, without an intermediate build step. In your scripts, you can
+register the Babel require shim like this:
+
+    require("babel-core/register")
+
+That will allow you to directly `require` the ES6 modules.
+
+## Plugins
+
+Acorn is designed support allow plugins which, within reasonable
+bounds, redefine the way the parser works. Plugins can add new token
+types and new tokenizer contexts (if necessary), and extend methods in
+the parser object. This is not a clean, elegant API—using it requires
+an understanding of Acorn's internals, and plugins are likely to break
+whenever those internals are significantly changed. But still, it is
+_possible_, in this way, to create parsers for JavaScript dialects
+without forking all of Acorn. And in principle it is even possible to
+combine such plugins, so that if you have, for example, a plugin for
+parsing types and a plugin for parsing JSX-style XML literals, you
+could load them both and parse code with both JSX tags and types.
+
+A plugin should register itself by adding a property to
+`acorn.plugins`, which holds a function. Calling `acorn.parse`, a
+`plugins` option can be passed, holding an object mapping plugin names
+to configuration values (or just `true` for plugins that don't take
+options). After the parser object has been created, the initialization
+functions for the chosen plugins are called with `(parser,
+configValue)` arguments. They are expected to use the `parser.extend`
+method to extend parser methods. For example, the `readToken` method
+could be extended like this:
+
+```javascript
+parser.extend("readToken", function(nextMethod) {
+  return function(code) {
+    console.log("Reading a token!")
+    return nextMethod.call(this, code)
+  }
+})
+```
+
+The `nextMethod` argument passed to `extend`'s second argument is the
+previous value of this method, and should usually be called through to
+whenever the extended method does not handle the call itself.
+
+Similarly, the loose parser allows plugins to register themselves via
+`acorn.pluginsLoose`.  The extension mechanism is the same as for the
+normal parser:
+
+```javascript
+looseParser.extend("readToken", function(nextMethod) {
+  return function() {
+    console.log("Reading a token in the loose parser!")
+    return nextMethod.call(this)
+  }
+})
+```
+
+### Existing plugins
+
+ - [`acorn-jsx`](https://github.com/RReverser/acorn-jsx): Parse [Facebook JSX syntax extensions](https://github.com/facebook/jsx)
+ - [`acorn-es7-plugin`](https://github.com/MatAtBread/acorn-es7-plugin/): Parse [async/await syntax proposal](https://github.com/tc39/ecmascript-asyncawait)
+ - [`acorn-object-spread`](https://github.com/UXtemple/acorn-object-spread): Parse [object spread syntax proposal](https://github.com/sebmarkbage/ecmascript-rest-spread)
+ - [`acorn-es7`](https://www.npmjs.com/package/acorn-es7): Parse [decorator syntax proposal](https://github.com/wycats/javascript-decorators)
+ - [`acorn-objj`](https://www.npmjs.com/package/acorn-objj): [Objective-J](http://www.cappuccino-project.org/learn/objective-j.html) language parser built as Acorn plugin
+ - [`acorn-object-rest-spread`](https://github.com/victor-homyakov/acorn-object-rest-spread) Parse [Object Rest/Spread Properties proposal](https://github.com/tc39/proposal-object-rest-spread), works with latest Acorn version (5.0.3)
+ - [`acorn-static-class-property-initializer`](https://github.com/victor-homyakov/acorn-static-class-property-initializer) Partial support for static class properties from [ES Class Fields & Static Properties Proposal](https://github.com/tc39/proposal-class-public-fields) to support static property initializers in [React components written as ES6+ classes](https://babeljs.io/blog/2015/06/07/react-on-es6-plus)
+ 
diff --git a/deps/acorn/bin/acorn b/deps/acorn/bin/acorn
new file mode 100755
index 0000000000..830c389641
--- /dev/null
+++ b/deps/acorn/bin/acorn
@@ -0,0 +1,69 @@
+#!/usr/bin/env node
+'use strict';
+
+var path = require('path');
+var fs = require('fs');
+var acorn = require('../dist/acorn.js');
+
+var infile;
+var forceFile;
+var silent = false;
+var compact = false;
+var tokenize = false;
+var options = {};
+
+function help(status) {
+  var print = (status == 0) ? console.log : console.error;
+  print("usage: " + path.basename(process.argv[1]) + " [--ecma3|--ecma5|--ecma6|--ecma7|--ecma8|--ecma9|...|--ecma2015|--ecma2016|--ecma2017|--ecma2018|...]");
+  print("        [--tokenize] [--locations] [---allow-hash-bang] [--compact] [--silent] [--module] [--help] [--] [infile]");
+  process.exit(status);
+}
+
+for (var i = 2; i < process.argv.length; ++i) {
+  var arg = process.argv[i];
+  if ((arg == "-" || arg[0] != "-") && !infile) { infile = arg; }
+  else if (arg == "--" && !infile && i + 2 == process.argv.length) { forceFile = infile = process.argv[++i]; }
+  else if (arg == "--locations") { options.locations = true; }
+  else if (arg == "--allow-hash-bang") { options.allowHashBang = true; }
+  else if (arg == "--silent") { silent = true; }
+  else if (arg == "--compact") { compact = true; }
+  else if (arg == "--help") { help(0); }
+  else if (arg == "--tokenize") { tokenize = true; }
+  else if (arg == "--module") { options.sourceType = "module"; }
+  else {
+    var match = arg.match(/^--ecma(\d+)$/);
+    if (match)
+      { options.ecmaVersion = +match[1]; }
+    else
+      { help(1); }
+  }
+}
+
+function run(code) {
+  var result;
+  try {
+    if (!tokenize) {
+      result = acorn.parse(code, options);
+    } else {
+      result = [];
+      var tokenizer$$1 = acorn.tokenizer(code, options), token;
+      do {
+        token = tokenizer$$1.getToken();
+        result.push(token);
+      } while (token.type != acorn.tokTypes.eof)
+    }
+  } catch (e) {
+    console.error(e.message);
+    process.exit(1);
+  }
+  if (!silent) { console.log(JSON.stringify(result, null, compact ? null : 2)); }
+}
+
+if (forceFile || infile && infile != "-") {
+  run(fs.readFileSync(infile, "utf8"));
+} else {
+  var code = "";
+  process.stdin.resume();
+  process.stdin.on("data", function (chunk) { return code += chunk; });
+  process.stdin.on("end", function () { return run(code); });
+}
diff --git a/deps/acorn/dist/.keep b/deps/acorn/dist/.keep
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/deps/acorn/dist/.keep
diff --git a/deps/acorn/dist/acorn.es.js b/deps/acorn/dist/acorn.es.js
new file mode 100644
index 0000000000..d7289102c2
--- /dev/null
+++ b/deps/acorn/dist/acorn.es.js
@@ -0,0 +1,3734 @@
+// Reserved word lists for various dialects of the language
+
+var reservedWords = {
+  3: "abstract boolean byte char class double enum export extends final float goto implements import int interface long native package private protected public short static super synchronized throws transient volatile",
+  5: "class enum extends super const export import",
+  6: "enum",
+  strict: "implements interface let package private protected public static yield",
+  strictBind: "eval arguments"
+};
+
+// And the keywords
+
+var ecma5AndLessKeywords = "break case catch continue debugger default do else finally for function if return switch throw try var while with null true false instanceof typeof void delete new in this";
+
+var keywords = {
+  5: ecma5AndLessKeywords,
+  6: ecma5AndLessKeywords + " const class extends export import super"
+};
+
+// ## Character categories
+
+// Big ugly regular expressions that match characters in the
+// whitespace, identifier, and identifier-start categories. These
+// are only applied when a character is found to actually have a
+// code point above 128.
+// Generated by `bin/generate-identifier-regex.js`.
+
+var nonASCIIidentifierStartChars = "\xaa\xb5\xba\xc0-\xd6\xd8-\xf6\xf8-\u02c1\u02c6-\u02d1\u02e0-\u02e4\u02ec\u02ee\u0370-\u0374\u0376\u0377\u037a-\u037d\u037f\u0386\u0388-\u038a\u038c\u038e-\u03a1\u03a3-\u03f5\u03f7-\u0481\u048a-\u052f\u0531-\u0556\u0559\u0561-\u0587\u05d0-\u05ea\u05f0-\u05f2\u0620-\u064a\u066e\u066f\u0671-\u06d3\u06d5\u06e5\u06e6\u06ee\u06ef\u06fa-\u06fc\u06ff\u0710\u0712-\u072f\u074d-\u07a5\u07b1\u07ca-\u07ea\u07f4\u07f5\u07fa\u0800-\u0815\u081a\u0824\u0828\u0840-\u0858\u08a0-\u08b4\u08b6-\u08bd\u0904-\u0939\u093d\u0950\u0958-\u0961\u0971-\u0980\u0985-\u098c\u098f\u0990\u0993-\u09a8\u09aa-\u09b0\u09b2\u09b6-\u09b9\u09bd\u09ce\u09dc\u09dd\u09df-\u09e1\u09f0\u09f1\u0a05-\u0a0a\u0a0f\u0a10\u0a13-\u0a28\u0a2a-\u0a30\u0a32\u0a33\u0a35\u0a36\u0a38\u0a39\u0a59-\u0a5c\u0a5e\u0a72-\u0a74\u0a85-\u0a8d\u0a8f-\u0a91\u0a93-\u0aa8\u0aaa-\u0ab0\u0ab2\u0ab3\u0ab5-\u0ab9\u0abd\u0ad0\u0ae0\u0ae1\u0af9\u0b05-\u0b0c\u0b0f\u0b10\u0b13-\u0b28\u0b2a-\u0b30\u0b32\u0b33\u0b35-\u0b39\u0b3d\u0b5c\u0b5d\u0b5f-\u0b61\u0b71\u0b83\u0b85-\u0b8a\u0b8e-\u0b90\u0b92-\u0b95\u0b99\u0b9a\u0b9c\u0b9e\u0b9f\u0ba3\u0ba4\u0ba8-\u0baa\u0bae-\u0bb9\u0bd0\u0c05-\u0c0c\u0c0e-\u0c10\u0c12-\u0c28\u0c2a-\u0c39\u0c3d\u0c58-\u0c5a\u0c60\u0c61\u0c80\u0c85-\u0c8c\u0c8e-\u0c90\u0c92-\u0ca8\u0caa-\u0cb3\u0cb5-\u0cb9\u0cbd\u0cde\u0ce0\u0ce1\u0cf1\u0cf2\u0d05-\u0d0c\u0d0e-\u0d10\u0d12-\u0d3a\u0d3d\u0d4e\u0d54-\u0d56\u0d5f-\u0d61\u0d7a-\u0d7f\u0d85-\u0d96\u0d9a-\u0db1\u0db3-\u0dbb\u0dbd\u0dc0-\u0dc6\u0e01-\u0e30\u0e32\u0e33\u0e40-\u0e46\u0e81\u0e82\u0e84\u0e87\u0e88\u0e8a\u0e8d\u0e94-\u0e97\u0e99-\u0e9f\u0ea1-\u0ea3\u0ea5\u0ea7\u0eaa\u0eab\u0ead-\u0eb0\u0eb2\u0eb3\u0ebd\u0ec0-\u0ec4\u0ec6\u0edc-\u0edf\u0f00\u0f40-\u0f47\u0f49-\u0f6c\u0f88-\u0f8c\u1000-\u102a\u103f\u1050-\u1055\u105a-\u105d\u1061\u1065\u1066\u106e-\u1070\u1075-\u1081\u108e\u10a0-\u10c5\u10c7\u10cd\u10d0-\u10fa\u10fc-\u1248\u124a-\u124d\u1250-\u1256\u1258\u125a-\u125d\u1260-\u1288\u128a-\u128d\u1290-\u12b0\u12b2-\u12b5\u12b8-\u12be\u12c0\u12c2-\u12c5\u12c8-\u12d6\u12d8-\u1310\u1312-\u1315\u1318-\u135a\u1380-\u138f\u13a0-\u13f5\u13f8-\u13fd\u1401-\u166c\u166f-\u167f\u1681-\u169a\u16a0-\u16ea\u16ee-\u16f8\u1700-\u170c\u170e-\u1711\u1720-\u1731\u1740-\u1751\u1760-\u176c\u176e-\u1770\u1780-\u17b3\u17d7\u17dc\u1820-\u1877\u1880-\u18a8\u18aa\u18b0-\u18f5\u1900-\u191e\u1950-\u196d\u1970-\u1974\u1980-\u19ab\u19b0-\u19c9\u1a00-\u1a16\u1a20-\u1a54\u1aa7\u1b05-\u1b33\u1b45-\u1b4b\u1b83-\u1ba0\u1bae\u1baf\u1bba-\u1be5\u1c00-\u1c23\u1c4d-\u1c4f\u1c5a-\u1c7d\u1c80-\u1c88\u1ce9-\u1cec\u1cee-\u1cf1\u1cf5\u1cf6\u1d00-\u1dbf\u1e00-\u1f15\u1f18-\u1f1d\u1f20-\u1f45\u1f48-\u1f4d\u1f50-\u1f57\u1f59\u1f5b\u1f5d\u1f5f-\u1f7d\u1f80-\u1fb4\u1fb6-\u1fbc\u1fbe\u1fc2-\u1fc4\u1fc6-\u1fcc\u1fd0-\u1fd3\u1fd6-\u1fdb\u1fe0-\u1fec\u1ff2-\u1ff4\u1ff6-\u1ffc\u2071\u207f\u2090-\u209c\u2102\u2107\u210a-\u2113\u2115\u2118-\u211d\u2124\u2126\u2128\u212a-\u2139\u213c-\u213f\u2145-\u2149\u214e\u2160-\u2188\u2c00-\u2c2e\u2c30-\u2c5e\u2c60-\u2ce4\u2ceb-\u2cee\u2cf2\u2cf3\u2d00-\u2d25\u2d27\u2d2d\u2d30-\u2d67\u2d6f\u2d80-\u2d96\u2da0-\u2da6\u2da8-\u2dae\u2db0-\u2db6\u2db8-\u2dbe\u2dc0-\u2dc6\u2dc8-\u2dce\u2dd0-\u2dd6\u2dd8-\u2dde\u3005-\u3007\u3021-\u3029\u3031-\u3035\u3038-\u303c\u3041-\u3096\u309b-\u309f\u30a1-\u30fa\u30fc-\u30ff\u3105-\u312d\u3131-\u318e\u31a0-\u31ba\u31f0-\u31ff\u3400-\u4db5\u4e00-\u9fd5\ua000-\ua48c\ua4d0-\ua4fd\ua500-\ua60c\ua610-\ua61f\ua62a\ua62b\ua640-\ua66e\ua67f-\ua69d\ua6a0-\ua6ef\ua717-\ua71f\ua722-\ua788\ua78b-\ua7ae\ua7b0-\ua7b7\ua7f7-\ua801\ua803-\ua805\ua807-\ua80a\ua80c-\ua822\ua840-\ua873\ua882-\ua8b3\ua8f2-\ua8f7\ua8fb\ua8fd\ua90a-\ua925\ua930-\ua946\ua960-\ua97c\ua984-\ua9b2\ua9cf\ua9e0-\ua9e4\ua9e6-\ua9ef\ua9fa-\ua9fe\uaa00-\uaa28\uaa40-\uaa42\uaa44-\uaa4b\uaa60-\uaa76\uaa7a\uaa7e-\uaaaf\uaab1\uaab5\uaab6\uaab9-\uaabd\uaac0\uaac2\uaadb-\uaadd\uaae0-\uaaea\uaaf2-\uaaf4\uab01-\uab06\uab09-\uab0e\uab11-\uab16\uab20-\uab26\uab28-\uab2e\uab30-\uab5a\uab5c-\uab65\uab70-\uabe2\uac00-\ud7a3\ud7b0-\ud7c6\ud7cb-\ud7fb\uf900-\ufa6d\ufa70-\ufad9\ufb00-\ufb06\ufb13-\ufb17\ufb1d\ufb1f-\ufb28\ufb2a-\ufb36\ufb38-\ufb3c\ufb3e\ufb40\ufb41\ufb43\ufb44\ufb46-\ufbb1\ufbd3-\ufd3d\ufd50-\ufd8f\ufd92-\ufdc7\ufdf0-\ufdfb\ufe70-\ufe74\ufe76-\ufefc\uff21-\uff3a\uff41-\uff5a\uff66-\uffbe\uffc2-\uffc7\uffca-\uffcf\uffd2-\uffd7\uffda-\uffdc";
+var nonASCIIidentifierChars = "\u200c\u200d\xb7\u0300-\u036f\u0387\u0483-\u0487\u0591-\u05bd\u05bf\u05c1\u05c2\u05c4\u05c5\u05c7\u0610-\u061a\u064b-\u0669\u0670\u06d6-\u06dc\u06df-\u06e4\u06e7\u06e8\u06ea-\u06ed\u06f0-\u06f9\u0711\u0730-\u074a\u07a6-\u07b0\u07c0-\u07c9\u07eb-\u07f3\u0816-\u0819\u081b-\u0823\u0825-\u0827\u0829-\u082d\u0859-\u085b\u08d4-\u08e1\u08e3-\u0903\u093a-\u093c\u093e-\u094f\u0951-\u0957\u0962\u0963\u0966-\u096f\u0981-\u0983\u09bc\u09be-\u09c4\u09c7\u09c8\u09cb-\u09cd\u09d7\u09e2\u09e3\u09e6-\u09ef\u0a01-\u0a03\u0a3c\u0a3e-\u0a42\u0a47\u0a48\u0a4b-\u0a4d\u0a51\u0a66-\u0a71\u0a75\u0a81-\u0a83\u0abc\u0abe-\u0ac5\u0ac7-\u0ac9\u0acb-\u0acd\u0ae2\u0ae3\u0ae6-\u0aef\u0b01-\u0b03\u0b3c\u0b3e-\u0b44\u0b47\u0b48\u0b4b-\u0b4d\u0b56\u0b57\u0b62\u0b63\u0b66-\u0b6f\u0b82\u0bbe-\u0bc2\u0bc6-\u0bc8\u0bca-\u0bcd\u0bd7\u0be6-\u0bef\u0c00-\u0c03\u0c3e-\u0c44\u0c46-\u0c48\u0c4a-\u0c4d\u0c55\u0c56\u0c62\u0c63\u0c66-\u0c6f\u0c81-\u0c83\u0cbc\u0cbe-\u0cc4\u0cc6-\u0cc8\u0cca-\u0ccd\u0cd5\u0cd6\u0ce2\u0ce3\u0ce6-\u0cef\u0d01-\u0d03\u0d3e-\u0d44\u0d46-\u0d48\u0d4a-\u0d4d\u0d57\u0d62\u0d63\u0d66-\u0d6f\u0d82\u0d83\u0dca\u0dcf-\u0dd4\u0dd6\u0dd8-\u0ddf\u0de6-\u0def\u0df2\u0df3\u0e31\u0e34-\u0e3a\u0e47-\u0e4e\u0e50-\u0e59\u0eb1\u0eb4-\u0eb9\u0ebb\u0ebc\u0ec8-\u0ecd\u0ed0-\u0ed9\u0f18\u0f19\u0f20-\u0f29\u0f35\u0f37\u0f39\u0f3e\u0f3f\u0f71-\u0f84\u0f86\u0f87\u0f8d-\u0f97\u0f99-\u0fbc\u0fc6\u102b-\u103e\u1040-\u1049\u1056-\u1059\u105e-\u1060\u1062-\u1064\u1067-\u106d\u1071-\u1074\u1082-\u108d\u108f-\u109d\u135d-\u135f\u1369-\u1371\u1712-\u1714\u1732-\u1734\u1752\u1753\u1772\u1773\u17b4-\u17d3\u17dd\u17e0-\u17e9\u180b-\u180d\u1810-\u1819\u18a9\u1920-\u192b\u1930-\u193b\u1946-\u194f\u19d0-\u19da\u1a17-\u1a1b\u1a55-\u1a5e\u1a60-\u1a7c\u1a7f-\u1a89\u1a90-\u1a99\u1ab0-\u1abd\u1b00-\u1b04\u1b34-\u1b44\u1b50-\u1b59\u1b6b-\u1b73\u1b80-\u1b82\u1ba1-\u1bad\u1bb0-\u1bb9\u1be6-\u1bf3\u1c24-\u1c37\u1c40-\u1c49\u1c50-\u1c59\u1cd0-\u1cd2\u1cd4-\u1ce8\u1ced\u1cf2-\u1cf4\u1cf8\u1cf9\u1dc0-\u1df5\u1dfb-\u1dff\u203f\u2040\u2054\u20d0-\u20dc\u20e1\u20e5-\u20f0\u2cef-\u2cf1\u2d7f\u2de0-\u2dff\u302a-\u302f\u3099\u309a\ua620-\ua629\ua66f\ua674-\ua67d\ua69e\ua69f\ua6f0\ua6f1\ua802\ua806\ua80b\ua823-\ua827\ua880\ua881\ua8b4-\ua8c5\ua8d0-\ua8d9\ua8e0-\ua8f1\ua900-\ua909\ua926-\ua92d\ua947-\ua953\ua980-\ua983\ua9b3-\ua9c0\ua9d0-\ua9d9\ua9e5\ua9f0-\ua9f9\uaa29-\uaa36\uaa43\uaa4c\uaa4d\uaa50-\uaa59\uaa7b-\uaa7d\uaab0\uaab2-\uaab4\uaab7\uaab8\uaabe\uaabf\uaac1\uaaeb-\uaaef\uaaf5\uaaf6\uabe3-\uabea\uabec\uabed\uabf0-\uabf9\ufb1e\ufe00-\ufe0f\ufe20-\ufe2f\ufe33\ufe34\ufe4d-\ufe4f\uff10-\uff19\uff3f";
+
+var nonASCIIidentifierStart = new RegExp("[" + nonASCIIidentifierStartChars + "]");
+var nonASCIIidentifier = new RegExp("[" + nonASCIIidentifierStartChars + nonASCIIidentifierChars + "]");
+
+nonASCIIidentifierStartChars = nonASCIIidentifierChars = null;
+
+// These are a run-length and offset encoded representation of the
+// >0xffff code points that are a valid part of identifiers. The
+// offset starts at 0x10000, and each pair of numbers represents an
+// offset to the next range, and then a size of the range. They were
+// generated by bin/generate-identifier-regex.js
+
+// eslint-disable-next-line comma-spacing
+var astralIdentifierStartCodes = [0,11,2,25,2,18,2,1,2,14,3,13,35,122,70,52,268,28,4,48,48,31,17,26,6,37,11,29,3,35,5,7,2,4,43,157,19,35,5,35,5,39,9,51,157,310,10,21,11,7,153,5,3,0,2,43,2,1,4,0,3,22,11,22,10,30,66,18,2,1,11,21,11,25,71,55,7,1,65,0,16,3,2,2,2,26,45,28,4,28,36,7,2,27,28,53,11,21,11,18,14,17,111,72,56,50,14,50,785,52,76,44,33,24,27,35,42,34,4,0,13,47,15,3,22,0,2,0,36,17,2,24,85,6,2,0,2,3,2,14,2,9,8,46,39,7,3,1,3,21,2,6,2,1,2,4,4,0,19,0,13,4,159,52,19,3,54,47,21,1,2,0,185,46,42,3,37,47,21,0,60,42,86,25,391,63,32,0,449,56,264,8,2,36,18,0,50,29,881,921,103,110,18,195,2749,1070,4050,582,8634,568,8,30,114,29,19,47,17,3,32,20,6,18,881,68,12,0,67,12,65,0,32,6124,20,754,9486,1,3071,106,6,12,4,8,8,9,5991,84,2,70,2,1,3,0,3,1,3,3,2,11,2,0,2,6,2,64,2,3,3,7,2,6,2,27,2,3,2,4,2,0,4,6,2,339,3,24,2,24,2,30,2,24,2,30,2,24,2,30,2,24,2,30,2,24,2,7,4149,196,60,67,1213,3,2,26,2,1,2,0,3,0,2,9,2,3,2,0,2,0,7,0,5,0,2,0,2,0,2,2,2,1,2,0,3,0,2,0,2,0,2,0,2,0,2,1,2,0,3,3,2,6,2,3,2,3,2,0,2,9,2,16,6,2,2,4,2,16,4421,42710,42,4148,12,221,3,5761,10591,541];
+
+// eslint-disable-next-line comma-spacing
+var astralIdentifierCodes = [509,0,227,0,150,4,294,9,1368,2,2,1,6,3,41,2,5,0,166,1,1306,2,54,14,32,9,16,3,46,10,54,9,7,2,37,13,2,9,52,0,13,2,49,13,10,2,4,9,83,11,7,0,161,11,6,9,7,3,57,0,2,6,3,1,3,2,10,0,11,1,3,6,4,4,193,17,10,9,87,19,13,9,214,6,3,8,28,1,83,16,16,9,82,12,9,9,84,14,5,9,423,9,838,7,2,7,17,9,57,21,2,13,19882,9,135,4,60,6,26,9,1016,45,17,3,19723,1,5319,4,4,5,9,7,3,6,31,3,149,2,1418,49,513,54,5,49,9,0,15,0,23,4,2,14,1361,6,2,16,3,6,2,1,2,4,2214,6,110,6,6,9,792487,239];
+
+// This has a complexity linear to the value of the code. The
+// assumption is that looking up astral identifier characters is
+// rare.
+function isInAstralSet(code, set) {
+  var pos = 0x10000;
+  for (var i = 0; i < set.length; i += 2) {
+    pos += set[i];
+    if (pos > code) { return false }
+    pos += set[i + 1];
+    if (pos >= code) { return true }
+  }
+}
+
+// Test whether a given character code starts an identifier.
+
+function isIdentifierStart(code, astral) {
+  if (code < 65) { return code === 36 }
+  if (code < 91) { return true }
+  if (code < 97) { return code === 95 }
+  if (code < 123) { return true }
+  if (code <= 0xffff) { return code >= 0xaa && nonASCIIidentifierStart.test(String.fromCharCode(code)) }
+  if (astral === false) { return false }
+  return isInAstralSet(code, astralIdentifierStartCodes)
+}
+
+// Test whether a given character is part of an identifier.
+
+function isIdentifierChar(code, astral) {
+  if (code < 48) { return code === 36 }
+  if (code < 58) { return true }
+  if (code < 65) { return false }
+  if (code < 91) { return true }
+  if (code < 97) { return code === 95 }
+  if (code < 123) { return true }
+  if (code <= 0xffff) { return code >= 0xaa && nonASCIIidentifier.test(String.fromCharCode(code)) }
+  if (astral === false) { return false }
+  return isInAstralSet(code, astralIdentifierStartCodes) || isInAstralSet(code, astralIdentifierCodes)
+}
+
+// ## Token types
+
+// The assignment of fine-grained, information-carrying type objects
+// allows the tokenizer to store the information it has about a
+// token in a way that is very cheap for the parser to look up.
+
+// All token type variables start with an underscore, to make them
+// easy to recognize.
+
+// The `beforeExpr` property is used to disambiguate between regular
+// expressions and divisions. It is set on all token types that can
+// be followed by an expression (thus, a slash after them would be a
+// regular expression).
+//
+// The `startsExpr` property is used to check if the token ends a
+// `yield` expression. It is set on all token types that either can
+// directly start an expression (like a quotation mark) or can
+// continue an expression (like the body of a string).
+//
+// `isLoop` marks a keyword as starting a loop, which is important
+// to know when parsing a label, in order to allow or disallow
+// continue jumps to that label.
+
+var TokenType = function TokenType(label, conf) {
+  if ( conf === void 0 ) conf = {};
+
+  this.label = label;
+  this.keyword = conf.keyword;
+  this.beforeExpr = !!conf.beforeExpr;
+  this.startsExpr = !!conf.startsExpr;
+  this.isLoop = !!conf.isLoop;
+  this.isAssign = !!conf.isAssign;
+  this.prefix = !!conf.prefix;
+  this.postfix = !!conf.postfix;
+  this.binop = conf.binop || null;
+  this.updateContext = null;
+};
+
+function binop(name, prec) {
+  return new TokenType(name, {beforeExpr: true, binop: prec})
+}
+var beforeExpr = {beforeExpr: true};
+var startsExpr = {startsExpr: true};
+
+// Map keyword names to token types.
+
+var keywords$1 = {};
+
+// Succinct definitions of keyword token types
+function kw(name, options) {
+  if ( options === void 0 ) options = {};
+
+  options.keyword = name;
+  return keywords$1[name] = new TokenType(name, options)
+}
+
+var types = {
+  num: new TokenType("num", startsExpr),
+  regexp: new TokenType("regexp", startsExpr),
+  string: new TokenType("string", startsExpr),
+  name: new TokenType("name", startsExpr),
+  eof: new TokenType("eof"),
+
+  // Punctuation token types.
+  bracketL: new TokenType("[", {beforeExpr: true, startsExpr: true}),
+  bracketR: new TokenType("]"),
+  braceL: new TokenType("{", {beforeExpr: true, startsExpr: true}),
+  braceR: new TokenType("}"),
+  parenL: new TokenType("(", {beforeExpr: true, startsExpr: true}),
+  parenR: new TokenType(")"),
+  comma: new TokenType(",", beforeExpr),
+  semi: new TokenType(";", beforeExpr),
+  colon: new TokenType(":", beforeExpr),
+  dot: new TokenType("."),
+  question: new TokenType("?", beforeExpr),
+  arrow: new TokenType("=>", beforeExpr),
+  template: new TokenType("template"),
+  invalidTemplate: new TokenType("invalidTemplate"),
+  ellipsis: new TokenType("...", beforeExpr),
+  backQuote: new TokenType("`", startsExpr),
+  dollarBraceL: new TokenType("${", {beforeExpr: true, startsExpr: true}),
+
+  // Operators. These carry several kinds of properties to help the
+  // parser use them properly (the presence of these properties is
+  // what categorizes them as operators).
+  //
+  // `binop`, when present, specifies that this operator is a binary
+  // operator, and will refer to its precedence.
+  //
+  // `prefix` and `postfix` mark the operator as a prefix or postfix
+  // unary operator.
+  //
+  // `isAssign` marks all of `=`, `+=`, `-=` etcetera, which act as
+  // binary operators with a very low precedence, that should result
+  // in AssignmentExpression nodes.
+
+  eq: new TokenType("=", {beforeExpr: true, isAssign: true}),
+  assign: new TokenType("_=", {beforeExpr: true, isAssign: true}),
+  incDec: new TokenType("++/--", {prefix: true, postfix: true, startsExpr: true}),
+  prefix: new TokenType("!/~", {beforeExpr: true, prefix: true, startsExpr: true}),
+  logicalOR: binop("||", 1),
+  logicalAND: binop("&&", 2),
+  bitwiseOR: binop("|", 3),
+  bitwiseXOR: binop("^", 4),
+  bitwiseAND: binop("&", 5),
+  equality: binop("==/!=/===/!==", 6),
+  relational: binop("</>/<=/>=", 7),
+  bitShift: binop("<</>>/>>>", 8),
+  plusMin: new TokenType("+/-", {beforeExpr: true, binop: 9, prefix: true, startsExpr: true}),
+  modulo: binop("%", 10),
+  star: binop("*", 10),
+  slash: binop("/", 10),
+  starstar: new TokenType("**", {beforeExpr: true}),
+
+  // Keyword token types.
+  _break: kw("break"),
+  _case: kw("case", beforeExpr),
+  _catch: kw("catch"),
+  _continue: kw("continue"),
+  _debugger: kw("debugger"),
+  _default: kw("default", beforeExpr),
+  _do: kw("do", {isLoop: true, beforeExpr: true}),
+  _else: kw("else", beforeExpr),
+  _finally: kw("finally"),
+  _for: kw("for", {isLoop: true}),
+  _function: kw("function", startsExpr),
+  _if: kw("if"),
+  _return: kw("return", beforeExpr),
+  _switch: kw("switch"),
+  _throw: kw("throw", beforeExpr),
+  _try: kw("try"),
+  _var: kw("var"),
+  _const: kw("const"),
+  _while: kw("while", {isLoop: true}),
+  _with: kw("with"),
+  _new: kw("new", {beforeExpr: true, startsExpr: true}),
+  _this: kw("this", startsExpr),
+  _super: kw("super", startsExpr),
+  _class: kw("class", startsExpr),
+  _extends: kw("extends", beforeExpr),
+  _export: kw("export"),
+  _import: kw("import"),
+  _null: kw("null", startsExpr),
+  _true: kw("true", startsExpr),
+  _false: kw("false", startsExpr),
+  _in: kw("in", {beforeExpr: true, binop: 7}),
+  _instanceof: kw("instanceof", {beforeExpr: true, binop: 7}),
+  _typeof: kw("typeof", {beforeExpr: true, prefix: true, startsExpr: true}),
+  _void: kw("void", {beforeExpr: true, prefix: true, startsExpr: true}),
+  _delete: kw("delete", {beforeExpr: true, prefix: true, startsExpr: true})
+};
+
+// Matches a whole line break (where CRLF is considered a single
+// line break). Used to count lines.
+
+var lineBreak = /\r\n?|\n|\u2028|\u2029/;
+var lineBreakG = new RegExp(lineBreak.source, "g");
+
+function isNewLine(code) {
+  return code === 10 || code === 13 || code === 0x2028 || code === 0x2029
+}
+
+var nonASCIIwhitespace = /[\u1680\u180e\u2000-\u200a\u202f\u205f\u3000\ufeff]/;
+
+var skipWhiteSpace = /(?:\s|\/\/.*|\/\*[^]*?\*\/)*/g;
+
+var ref = Object.prototype;
+var hasOwnProperty = ref.hasOwnProperty;
+var toString = ref.toString;
+
+// Checks if an object has a property.
+
+function has(obj, propName) {
+  return hasOwnProperty.call(obj, propName)
+}
+
+var isArray = Array.isArray || (function (obj) { return (
+  toString.call(obj) === "[object Array]"
+); });
+
+// These are used when `options.locations` is on, for the
+// `startLoc` and `endLoc` properties.
+
+var Position = function Position(line, col) {
+  this.line = line;
+  this.column = col;
+};
+
+Position.prototype.offset = function offset (n) {
+  return new Position(this.line, this.column + n)
+};
+
+var SourceLocation = function SourceLocation(p, start, end) {
+  this.start = start;
+  this.end = end;
+  if (p.sourceFile !== null) { this.source = p.sourceFile; }
+};
+
+// The `getLineInfo` function is mostly useful when the
+// `locations` option is off (for performance reasons) and you
+// want to find the line/column position for a given character
+// offset. `input` should be the code string that the offset refers
+// into.
+
+function getLineInfo(input, offset) {
+  for (var line = 1, cur = 0;;) {
+    lineBreakG.lastIndex = cur;
+    var match = lineBreakG.exec(input);
+    if (match && match.index < offset) {
+      ++line;
+      cur = match.index + match[0].length;
+    } else {
+      return new Position(line, offset - cur)
+    }
+  }
+}
+
+// A second optional argument can be given to further configure
+// the parser process. These options are recognized:
+
+var defaultOptions = {
+  // `ecmaVersion` indicates the ECMAScript version to parse. Must
+  // be either 3, 5, 6 (2015), 7 (2016), or 8 (2017). This influences support
+  // for strict mode, the set of reserved words, and support for
+  // new syntax features. The default is 7.
+  ecmaVersion: 7,
+  // `sourceType` indicates the mode the code should be parsed in.
+  // Can be either `"script"` or `"module"`. This influences global
+  // strict mode and parsing of `import` and `export` declarations.
+  sourceType: "script",
+  // `onInsertedSemicolon` can be a callback that will be called
+  // when a semicolon is automatically inserted. It will be passed
+  // th position of the comma as an offset, and if `locations` is
+  // enabled, it is given the location as a `{line, column}` object
+  // as second argument.
+  onInsertedSemicolon: null,
+  // `onTrailingComma` is similar to `onInsertedSemicolon`, but for
+  // trailing commas.
+  onTrailingComma: null,
+  // By default, reserved words are only enforced if ecmaVersion >= 5.
+  // Set `allowReserved` to a boolean value to explicitly turn this on
+  // an off. When this option has the value "never", reserved words
+  // and keywords can also not be used as property names.
+  allowReserved: null,
+  // When enabled, a return at the top level is not considered an
+  // error.
+  allowReturnOutsideFunction: false,
+  // When enabled, import/export statements are not constrained to
+  // appearing at the top of the program.
+  allowImportExportEverywhere: false,
+  // When enabled, hashbang directive in the beginning of file
+  // is allowed and treated as a line comment.
+  allowHashBang: false,
+  // When `locations` is on, `loc` properties holding objects with
+  // `start` and `end` properties in `{line, column}` form (with
+  // line being 1-based and column 0-based) will be attached to the
+  // nodes.
+  locations: false,
+  // A function can be passed as `onToken` option, which will
+  // cause Acorn to call that function with object in the same
+  // format as tokens returned from `tokenizer().getToken()`. Note
+  // that you are not allowed to call the parser from the
+  // callback—that will corrupt its internal state.
+  onToken: null,
+  // A function can be passed as `onComment` option, which will
+  // cause Acorn to call that function with `(block, text, start,
+  // end)` parameters whenever a comment is skipped. `block` is a
+  // boolean indicating whether this is a block (`/* */`) comment,
+  // `text` is the content of the comment, and `start` and `end` are
+  // character offsets that denote the start and end of the comment.
+  // When the `locations` option is on, two more parameters are
+  // passed, the full `{line, column}` locations of the start and
+  // end of the comments. Note that you are not allowed to call the
+  // parser from the callback—that will corrupt its internal state.
+  onComment: null,
+  // Nodes have their start and end characters offsets recorded in
+  // `start` and `end` properties (directly on the node, rather than
+  // the `loc` object, which holds line/column data. To also add a
+  // [semi-standardized][range] `range` property holding a `[start,
+  // end]` array with the same numbers, set the `ranges` option to
+  // `true`.
+  //
+  // [range]: https://bugzilla.mozilla.org/show_bug.cgi?id=745678
+  ranges: false,
+  // It is possible to parse multiple files into a single AST by
+  // passing the tree produced by parsing the first file as
+  // `program` option in subsequent parses. This will add the
+  // toplevel forms of the parsed file to the `Program` (top) node
+  // of an existing parse tree.
+  program: null,
+  // When `locations` is on, you can pass this to record the source
+  // file in every node's `loc` object.
+  sourceFile: null,
+  // This value, if given, is stored in every node, whether
+  // `locations` is on or off.
+  directSourceFile: null,
+  // When enabled, parenthesized expressions are represented by
+  // (non-standard) ParenthesizedExpression nodes
+  preserveParens: false,
+  plugins: {}
+};
+
+// Interpret and default an options object
+
+function getOptions(opts) {
+  var options = {};
+
+  for (var opt in defaultOptions)
+    { options[opt] = opts && has(opts, opt) ? opts[opt] : defaultOptions[opt]; }
+
+  if (options.ecmaVersion >= 2015)
+    { options.ecmaVersion -= 2009; }
+
+  if (options.allowReserved == null)
+    { options.allowReserved = options.ecmaVersion < 5; }
+
+  if (isArray(options.onToken)) {
+    var tokens = options.onToken;
+    options.onToken = function (token) { return tokens.push(token); };
+  }
+  if (isArray(options.onComment))
+    { options.onComment = pushComment(options, options.onComment); }
+
+  return options
+}
+
+function pushComment(options, array) {
+  return function(block, text, start, end, startLoc, endLoc) {
+    var comment = {
+      type: block ? "Block" : "Line",
+      value: text,
+      start: start,
+      end: end
+    };
+    if (options.locations)
+      { comment.loc = new SourceLocation(this, startLoc, endLoc); }
+    if (options.ranges)
+      { comment.range = [start, end]; }
+    array.push(comment);
+  }
+}
+
+// Registered plugins
+var plugins = {};
+
+function keywordRegexp(words) {
+  return new RegExp("^(?:" + words.replace(/ /g, "|") + ")$")
+}
+
+var Parser = function Parser(options, input, startPos) {
+  this.options = options = getOptions(options);
+  this.sourceFile = options.sourceFile;
+  this.keywords = keywordRegexp(keywords[options.ecmaVersion >= 6 ? 6 : 5]);
+  var reserved = "";
+  if (!options.allowReserved) {
+    for (var v = options.ecmaVersion;; v--)
+      { if (reserved = reservedWords[v]) { break } }
+    if (options.sourceType == "module") { reserved += " await"; }
+  }
+  this.reservedWords = keywordRegexp(reserved);
+  var reservedStrict = (reserved ? reserved + " " : "") + reservedWords.strict;
+  this.reservedWordsStrict = keywordRegexp(reservedStrict);
+  this.reservedWordsStrictBind = keywordRegexp(reservedStrict + " " + reservedWords.strictBind);
+  this.input = String(input);
+
+  // Used to signal to callers of `readWord1` whether the word
+  // contained any escape sequences. This is needed because words with
+  // escape sequences must not be interpreted as keywords.
+  this.containsEsc = false;
+
+  // Load plugins
+  this.loadPlugins(options.plugins);
+
+  // Set up token state
+
+  // The current position of the tokenizer in the input.
+  if (startPos) {
+    this.pos = startPos;
+    this.lineStart = this.input.lastIndexOf("\n", startPos - 1) + 1;
+    this.curLine = this.input.slice(0, this.lineStart).split(lineBreak).length;
+  } else {
+    this.pos = this.lineStart = 0;
+    this.curLine = 1;
+  }
+
+  // Properties of the current token:
+  // Its type
+  this.type = types.eof;
+  // For tokens that include more information than their type, the value
+  this.value = null;
+  // Its start and end offset
+  this.start = this.end = this.pos;
+  // And, if locations are used, the {line, column} object
+  // corresponding to those offsets
+  this.startLoc = this.endLoc = this.curPosition();
+
+  // Position information for the previous token
+  this.lastTokEndLoc = this.lastTokStartLoc = null;
+  this.lastTokStart = this.lastTokEnd = this.pos;
+
+  // The context stack is used to superficially track syntactic
+  // context to predict whether a regular expression is allowed in a
+  // given position.
+  this.context = this.initialContext();
+  this.exprAllowed = true;
+
+  // Figure out if it's a module code.
+  this.inModule = options.sourceType === "module";
+  this.strict = this.inModule || this.strictDirective(this.pos);
+
+  // Used to signify the start of a potential arrow function
+  this.potentialArrowAt = -1;
+
+  // Flags to track whether we are in a function, a generator, an async function.
+  this.inFunction = this.inGenerator = this.inAsync = false;
+  // Positions to delayed-check that yield/await does not exist in default parameters.
+  this.yieldPos = this.awaitPos = 0;
+  // Labels in scope.
+  this.labels = [];
+
+  // If enabled, skip leading hashbang line.
+  if (this.pos === 0 && options.allowHashBang && this.input.slice(0, 2) === "#!")
+    { this.skipLineComment(2); }
+
+  // Scope tracking for duplicate variable names (see scope.js)
+  this.scopeStack = [];
+  this.enterFunctionScope();
+};
+
+// DEPRECATED Kept for backwards compatibility until 3.0 in case a plugin uses them
+Parser.prototype.isKeyword = function isKeyword (word) { return this.keywords.test(word) };
+Parser.prototype.isReservedWord = function isReservedWord (word) { return this.reservedWords.test(word) };
+
+Parser.prototype.extend = function extend (name, f) {
+  this[name] = f(this[name]);
+};
+
+Parser.prototype.loadPlugins = function loadPlugins (pluginConfigs) {
+    var this$1 = this;
+
+  for (var name in pluginConfigs) {
+    var plugin = plugins[name];
+    if (!plugin) { throw new Error("Plugin '" + name + "' not found") }
+    plugin(this$1, pluginConfigs[name]);
+  }
+};
+
+Parser.prototype.parse = function parse () {
+  var node = this.options.program || this.startNode();
+  this.nextToken();
+  return this.parseTopLevel(node)
+};
+
+var pp = Parser.prototype;
+
+// ## Parser utilities
+
+var literal = /^(?:'((?:\\.|[^'])*?)'|"((?:\\.|[^"])*?)"|;)/;
+pp.strictDirective = function(start) {
+  var this$1 = this;
+
+  for (;;) {
+    skipWhiteSpace.lastIndex = start;
+    start += skipWhiteSpace.exec(this$1.input)[0].length;
+    var match = literal.exec(this$1.input.slice(start));
+    if (!match) { return false }
+    if ((match[1] || match[2]) == "use strict") { return true }
+    start += match[0].length;
+  }
+};
+
+// Predicate that tests whether the next token is of the given
+// type, and if yes, consumes it as a side effect.
+
+pp.eat = function(type) {
+  if (this.type === type) {
+    this.next();
+    return true
+  } else {
+    return false
+  }
+};
+
+// Tests whether parsed token is a contextual keyword.
+
+pp.isContextual = function(name) {
+  return this.type === types.name && this.value === name
+};
+
+// Consumes contextual keyword if possible.
+
+pp.eatContextual = function(name) {
+  return this.value === name && this.eat(types.name)
+};
+
+// Asserts that following token is given contextual keyword.
+
+pp.expectContextual = function(name) {
+  if (!this.eatContextual(name)) { this.unexpected(); }
+};
+
+// Test whether a semicolon can be inserted at the current position.
+
+pp.canInsertSemicolon = function() {
+  return this.type === types.eof ||
+    this.type === types.braceR ||
+    lineBreak.test(this.input.slice(this.lastTokEnd, this.start))
+};
+
+pp.insertSemicolon = function() {
+  if (this.canInsertSemicolon()) {
+    if (this.options.onInsertedSemicolon)
+      { this.options.onInsertedSemicolon(this.lastTokEnd, this.lastTokEndLoc); }
+    return true
+  }
+};
+
+// Consume a semicolon, or, failing that, see if we are allowed to
+// pretend that there is a semicolon at this position.
+
+pp.semicolon = function() {
+  if (!this.eat(types.semi) && !this.insertSemicolon()) { this.unexpected(); }
+};
+
+pp.afterTrailingComma = function(tokType, notNext) {
+  if (this.type == tokType) {
+    if (this.options.onTrailingComma)
+      { this.options.onTrailingComma(this.lastTokStart, this.lastTokStartLoc); }
+    if (!notNext)
+      { this.next(); }
+    return true
+  }
+};
+
+// Expect a token of a given type. If found, consume it, otherwise,
+// raise an unexpected token error.
+
+pp.expect = function(type) {
+  this.eat(type) || this.unexpected();
+};
+
+// Raise an unexpected token error.
+
+pp.unexpected = function(pos) {
+  this.raise(pos != null ? pos : this.start, "Unexpected token");
+};
+
+function DestructuringErrors() {
+  this.shorthandAssign =
+  this.trailingComma =
+  this.parenthesizedAssign =
+  this.parenthesizedBind =
+    -1;
+}
+
+pp.checkPatternErrors = function(refDestructuringErrors, isAssign) {
+  if (!refDestructuringErrors) { return }
+  if (refDestructuringErrors.trailingComma > -1)
+    { this.raiseRecoverable(refDestructuringErrors.trailingComma, "Comma is not permitted after the rest element"); }
+  var parens = isAssign ? refDestructuringErrors.parenthesizedAssign : refDestructuringErrors.parenthesizedBind;
+  if (parens > -1) { this.raiseRecoverable(parens, "Parenthesized pattern"); }
+};
+
+pp.checkExpressionErrors = function(refDestructuringErrors, andThrow) {
+  var pos = refDestructuringErrors ? refDestructuringErrors.shorthandAssign : -1;
+  if (!andThrow) { return pos >= 0 }
+  if (pos > -1) { this.raise(pos, "Shorthand property assignments are valid only in destructuring patterns"); }
+};
+
+pp.checkYieldAwaitInDefaultParams = function() {
+  if (this.yieldPos && (!this.awaitPos || this.yieldPos < this.awaitPos))
+    { this.raise(this.yieldPos, "Yield expression cannot be a default value"); }
+  if (this.awaitPos)
+    { this.raise(this.awaitPos, "Await expression cannot be a default value"); }
+};
+
+pp.isSimpleAssignTarget = function(expr) {
+  if (expr.type === "ParenthesizedExpression")
+    { return this.isSimpleAssignTarget(expr.expression) }
+  return expr.type === "Identifier" || expr.type === "MemberExpression"
+};
+
+var pp$1 = Parser.prototype;
+
+// ### Statement parsing
+
+// Parse a program. Initializes the parser, reads any number of
+// statements, and wraps them in a Program node.  Optionally takes a
+// `program` argument.  If present, the statements will be appended
+// to its body instead of creating a new node.
+
+pp$1.parseTopLevel = function(node) {
+  var this$1 = this;
+
+  var exports = {};
+  if (!node.body) { node.body = []; }
+  while (this.type !== types.eof) {
+    var stmt = this$1.parseStatement(true, true, exports);
+    node.body.push(stmt);
+  }
+  this.adaptDirectivePrologue(node.body);
+  this.next();
+  if (this.options.ecmaVersion >= 6) {
+    node.sourceType = this.options.sourceType;
+  }
+  return this.finishNode(node, "Program")
+};
+
+var loopLabel = {kind: "loop"};
+var switchLabel = {kind: "switch"};
+
+pp$1.isLet = function() {
+  if (this.type !== types.name || this.options.ecmaVersion < 6 || this.value != "let") { return false }
+  skipWhiteSpace.lastIndex = this.pos;
+  var skip = skipWhiteSpace.exec(this.input);
+  var next = this.pos + skip[0].length, nextCh = this.input.charCodeAt(next);
+  if (nextCh === 91 || nextCh == 123) { return true } // '{' and '['
+  if (isIdentifierStart(nextCh, true)) {
+    var pos = next + 1;
+    while (isIdentifierChar(this.input.charCodeAt(pos), true)) { ++pos; }
+    var ident = this.input.slice(next, pos);
+    if (!this.isKeyword(ident)) { return true }
+  }
+  return false
+};
+
+// check 'async [no LineTerminator here] function'
+// - 'async /*foo*/ function' is OK.
+// - 'async /*\n*/ function' is invalid.
+pp$1.isAsyncFunction = function() {
+  if (this.type !== types.name || this.options.ecmaVersion < 8 || this.value != "async")
+    { return false }
+
+  skipWhiteSpace.lastIndex = this.pos;
+  var skip = skipWhiteSpace.exec(this.input);
+  var next = this.pos + skip[0].length;
+  return !lineBreak.test(this.input.slice(this.pos, next)) &&
+    this.input.slice(next, next + 8) === "function" &&
+    (next + 8 == this.input.length || !isIdentifierChar(this.input.charAt(next + 8)))
+};
+
+// Parse a single statement.
+//
+// If expecting a statement and finding a slash operator, parse a
+// regular expression literal. This is to handle cases like
+// `if (foo) /blah/.exec(foo)`, where looking at the previous token
+// does not help.
+
+pp$1.parseStatement = function(declaration, topLevel, exports) {
+  var starttype = this.type, node = this.startNode(), kind;
+
+  if (this.isLet()) {
+    starttype = types._var;
+    kind = "let";
+  }
+
+  // Most types of statements are recognized by the keyword they
+  // start with. Many are trivial to parse, some require a bit of
+  // complexity.
+
+  switch (starttype) {
+  case types._break: case types._continue: return this.parseBreakContinueStatement(node, starttype.keyword)
+  case types._debugger: return this.parseDebuggerStatement(node)
+  case types._do: return this.parseDoStatement(node)
+  case types._for: return this.parseForStatement(node)
+  case types._function:
+    if (!declaration && this.options.ecmaVersion >= 6) { this.unexpected(); }
+    return this.parseFunctionStatement(node, false)
+  case types._class:
+    if (!declaration) { this.unexpected(); }
+    return this.parseClass(node, true)
+  case types._if: return this.parseIfStatement(node)
+  case types._return: return this.parseReturnStatement(node)
+  case types._switch: return this.parseSwitchStatement(node)
+  case types._throw: return this.parseThrowStatement(node)
+  case types._try: return this.parseTryStatement(node)
+  case types._const: case types._var:
+    kind = kind || this.value;
+    if (!declaration && kind != "var") { this.unexpected(); }
+    return this.parseVarStatement(node, kind)
+  case types._while: return this.parseWhileStatement(node)
+  case types._with: return this.parseWithStatement(node)
+  case types.braceL: return this.parseBlock()
+  case types.semi: return this.parseEmptyStatement(node)
+  case types._export:
+  case types._import:
+    if (!this.options.allowImportExportEverywhere) {
+      if (!topLevel)
+        { this.raise(this.start, "'import' and 'export' may only appear at the top level"); }
+      if (!this.inModule)
+        { this.raise(this.start, "'import' and 'export' may appear only with 'sourceType: module'"); }
+    }
+    return starttype === types._import ? this.parseImport(node) : this.parseExport(node, exports)
+
+    // If the statement does not start with a statement keyword or a
+    // brace, it's an ExpressionStatement or LabeledStatement. We
+    // simply start parsing an expression, and afterwards, if the
+    // next token is a colon and the expression was a simple
+    // Identifier node, we switch to interpreting it as a label.
+  default:
+    if (this.isAsyncFunction() && declaration) {
+      this.next();
+      return this.parseFunctionStatement(node, true)
+    }
+
+    var maybeName = this.value, expr = this.parseExpression();
+    if (starttype === types.name && expr.type === "Identifier" && this.eat(types.colon))
+      { return this.parseLabeledStatement(node, maybeName, expr) }
+    else { return this.parseExpressionStatement(node, expr) }
+  }
+};
+
+pp$1.parseBreakContinueStatement = function(node, keyword) {
+  var this$1 = this;
+
+  var isBreak = keyword == "break";
+  this.next();
+  if (this.eat(types.semi) || this.insertSemicolon()) { node.label = null; }
+  else if (this.type !== types.name) { this.unexpected(); }
+  else {
+    node.label = this.parseIdent();
+    this.semicolon();
+  }
+
+  // Verify that there is an actual destination to break or
+  // continue to.
+  var i = 0;
+  for (; i < this.labels.length; ++i) {
+    var lab = this$1.labels[i];
+    if (node.label == null || lab.name === node.label.name) {
+      if (lab.kind != null && (isBreak || lab.kind === "loop")) { break }
+      if (node.label && isBreak) { break }
+    }
+  }
+  if (i === this.labels.length) { this.raise(node.start, "Unsyntactic " + keyword); }
+  return this.finishNode(node, isBreak ? "BreakStatement" : "ContinueStatement")
+};
+
+pp$1.parseDebuggerStatement = function(node) {
+  this.next();
+  this.semicolon();
+  return this.finishNode(node, "DebuggerStatement")
+};
+
+pp$1.parseDoStatement = function(node) {
+  this.next();
+  this.labels.push(loopLabel);
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  this.expect(types._while);
+  node.test = this.parseParenExpression();
+  if (this.options.ecmaVersion >= 6)
+    { this.eat(types.semi); }
+  else
+    { this.semicolon(); }
+  return this.finishNode(node, "DoWhileStatement")
+};
+
+// Disambiguating between a `for` and a `for`/`in` or `for`/`of`
+// loop is non-trivial. Basically, we have to parse the init `var`
+// statement or expression, disallowing the `in` operator (see
+// the second parameter to `parseExpression`), and then check
+// whether the next token is `in` or `of`. When there is no init
+// part (semicolon immediately after the opening parenthesis), it
+// is a regular `for` loop.
+
+pp$1.parseForStatement = function(node) {
+  this.next();
+  this.labels.push(loopLabel);
+  this.enterLexicalScope();
+  this.expect(types.parenL);
+  if (this.type === types.semi) { return this.parseFor(node, null) }
+  var isLet = this.isLet();
+  if (this.type === types._var || this.type === types._const || isLet) {
+    var init$1 = this.startNode(), kind = isLet ? "let" : this.value;
+    this.next();
+    this.parseVar(init$1, true, kind);
+    this.finishNode(init$1, "VariableDeclaration");
+    if ((this.type === types._in || (this.options.ecmaVersion >= 6 && this.isContextual("of"))) && init$1.declarations.length === 1 &&
+        !(kind !== "var" && init$1.declarations[0].init))
+      { return this.parseForIn(node, init$1) }
+    return this.parseFor(node, init$1)
+  }
+  var refDestructuringErrors = new DestructuringErrors;
+  var init = this.parseExpression(true, refDestructuringErrors);
+  if (this.type === types._in || (this.options.ecmaVersion >= 6 && this.isContextual("of"))) {
+    this.toAssignable(init);
+    this.checkLVal(init);
+    this.checkPatternErrors(refDestructuringErrors, true);
+    return this.parseForIn(node, init)
+  } else {
+    this.checkExpressionErrors(refDestructuringErrors, true);
+  }
+  return this.parseFor(node, init)
+};
+
+pp$1.parseFunctionStatement = function(node, isAsync) {
+  this.next();
+  return this.parseFunction(node, true, false, isAsync)
+};
+
+pp$1.isFunction = function() {
+  return this.type === types._function || this.isAsyncFunction()
+};
+
+pp$1.parseIfStatement = function(node) {
+  this.next();
+  node.test = this.parseParenExpression();
+  // allow function declarations in branches, but only in non-strict mode
+  node.consequent = this.parseStatement(!this.strict && this.isFunction());
+  node.alternate = this.eat(types._else) ? this.parseStatement(!this.strict && this.isFunction()) : null;
+  return this.finishNode(node, "IfStatement")
+};
+
+pp$1.parseReturnStatement = function(node) {
+  if (!this.inFunction && !this.options.allowReturnOutsideFunction)
+    { this.raise(this.start, "'return' outside of function"); }
+  this.next();
+
+  // In `return` (and `break`/`continue`), the keywords with
+  // optional arguments, we eagerly look for a semicolon or the
+  // possibility to insert one.
+
+  if (this.eat(types.semi) || this.insertSemicolon()) { node.argument = null; }
+  else { node.argument = this.parseExpression(); this.semicolon(); }
+  return this.finishNode(node, "ReturnStatement")
+};
+
+pp$1.parseSwitchStatement = function(node) {
+  var this$1 = this;
+
+  this.next();
+  node.discriminant = this.parseParenExpression();
+  node.cases = [];
+  this.expect(types.braceL);
+  this.labels.push(switchLabel);
+  this.enterLexicalScope();
+
+  // Statements under must be grouped (by label) in SwitchCase
+  // nodes. `cur` is used to keep the node that we are currently
+  // adding statements to.
+
+  var cur;
+  for (var sawDefault = false; this.type != types.braceR;) {
+    if (this$1.type === types._case || this$1.type === types._default) {
+      var isCase = this$1.type === types._case;
+      if (cur) { this$1.finishNode(cur, "SwitchCase"); }
+      node.cases.push(cur = this$1.startNode());
+      cur.consequent = [];
+      this$1.next();
+      if (isCase) {
+        cur.test = this$1.parseExpression();
+      } else {
+        if (sawDefault) { this$1.raiseRecoverable(this$1.lastTokStart, "Multiple default clauses"); }
+        sawDefault = true;
+        cur.test = null;
+      }
+      this$1.expect(types.colon);
+    } else {
+      if (!cur) { this$1.unexpected(); }
+      cur.consequent.push(this$1.parseStatement(true));
+    }
+  }
+  this.exitLexicalScope();
+  if (cur) { this.finishNode(cur, "SwitchCase"); }
+  this.next(); // Closing brace
+  this.labels.pop();
+  return this.finishNode(node, "SwitchStatement")
+};
+
+pp$1.parseThrowStatement = function(node) {
+  this.next();
+  if (lineBreak.test(this.input.slice(this.lastTokEnd, this.start)))
+    { this.raise(this.lastTokEnd, "Illegal newline after throw"); }
+  node.argument = this.parseExpression();
+  this.semicolon();
+  return this.finishNode(node, "ThrowStatement")
+};
+
+// Reused empty array added for node fields that are always empty.
+
+var empty = [];
+
+pp$1.parseTryStatement = function(node) {
+  this.next();
+  node.block = this.parseBlock();
+  node.handler = null;
+  if (this.type === types._catch) {
+    var clause = this.startNode();
+    this.next();
+    this.expect(types.parenL);
+    clause.param = this.parseBindingAtom();
+    this.enterLexicalScope();
+    this.checkLVal(clause.param, "let");
+    this.expect(types.parenR);
+    clause.body = this.parseBlock(false);
+    this.exitLexicalScope();
+    node.handler = this.finishNode(clause, "CatchClause");
+  }
+  node.finalizer = this.eat(types._finally) ? this.parseBlock() : null;
+  if (!node.handler && !node.finalizer)
+    { this.raise(node.start, "Missing catch or finally clause"); }
+  return this.finishNode(node, "TryStatement")
+};
+
+pp$1.parseVarStatement = function(node, kind) {
+  this.next();
+  this.parseVar(node, false, kind);
+  this.semicolon();
+  return this.finishNode(node, "VariableDeclaration")
+};
+
+pp$1.parseWhileStatement = function(node) {
+  this.next();
+  node.test = this.parseParenExpression();
+  this.labels.push(loopLabel);
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  return this.finishNode(node, "WhileStatement")
+};
+
+pp$1.parseWithStatement = function(node) {
+  if (this.strict) { this.raise(this.start, "'with' in strict mode"); }
+  this.next();
+  node.object = this.parseParenExpression();
+  node.body = this.parseStatement(false);
+  return this.finishNode(node, "WithStatement")
+};
+
+pp$1.parseEmptyStatement = function(node) {
+  this.next();
+  return this.finishNode(node, "EmptyStatement")
+};
+
+pp$1.parseLabeledStatement = function(node, maybeName, expr) {
+  var this$1 = this;
+
+  for (var i$1 = 0, list = this$1.labels; i$1 < list.length; i$1 += 1)
+    {
+    var label = list[i$1];
+
+    if (label.name === maybeName)
+      { this$1.raise(expr.start, "Label '" + maybeName + "' is already declared");
+  } }
+  var kind = this.type.isLoop ? "loop" : this.type === types._switch ? "switch" : null;
+  for (var i = this.labels.length - 1; i >= 0; i--) {
+    var label$1 = this$1.labels[i];
+    if (label$1.statementStart == node.start) {
+      label$1.statementStart = this$1.start;
+      label$1.kind = kind;
+    } else { break }
+  }
+  this.labels.push({name: maybeName, kind: kind, statementStart: this.start});
+  node.body = this.parseStatement(true);
+  if (node.body.type == "ClassDeclaration" ||
+      node.body.type == "VariableDeclaration" && node.body.kind != "var" ||
+      node.body.type == "FunctionDeclaration" && (this.strict || node.body.generator))
+    { this.raiseRecoverable(node.body.start, "Invalid labeled declaration"); }
+  this.labels.pop();
+  node.label = expr;
+  return this.finishNode(node, "LabeledStatement")
+};
+
+pp$1.parseExpressionStatement = function(node, expr) {
+  node.expression = expr;
+  this.semicolon();
+  return this.finishNode(node, "ExpressionStatement")
+};
+
+// Parse a semicolon-enclosed block of statements, handling `"use
+// strict"` declarations when `allowStrict` is true (used for
+// function bodies).
+
+pp$1.parseBlock = function(createNewLexicalScope) {
+  var this$1 = this;
+  if ( createNewLexicalScope === void 0 ) createNewLexicalScope = true;
+
+  var node = this.startNode();
+  node.body = [];
+  this.expect(types.braceL);
+  if (createNewLexicalScope) {
+    this.enterLexicalScope();
+  }
+  while (!this.eat(types.braceR)) {
+    var stmt = this$1.parseStatement(true);
+    node.body.push(stmt);
+  }
+  if (createNewLexicalScope) {
+    this.exitLexicalScope();
+  }
+  return this.finishNode(node, "BlockStatement")
+};
+
+// Parse a regular `for` loop. The disambiguation code in
+// `parseStatement` will already have parsed the init statement or
+// expression.
+
+pp$1.parseFor = function(node, init) {
+  node.init = init;
+  this.expect(types.semi);
+  node.test = this.type === types.semi ? null : this.parseExpression();
+  this.expect(types.semi);
+  node.update = this.type === types.parenR ? null : this.parseExpression();
+  this.expect(types.parenR);
+  this.exitLexicalScope();
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  return this.finishNode(node, "ForStatement")
+};
+
+// Parse a `for`/`in` and `for`/`of` loop, which are almost
+// same from parser's perspective.
+
+pp$1.parseForIn = function(node, init) {
+  var type = this.type === types._in ? "ForInStatement" : "ForOfStatement";
+  this.next();
+  node.left = init;
+  node.right = this.parseExpression();
+  this.expect(types.parenR);
+  this.exitLexicalScope();
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  return this.finishNode(node, type)
+};
+
+// Parse a list of variable declarations.
+
+pp$1.parseVar = function(node, isFor, kind) {
+  var this$1 = this;
+
+  node.declarations = [];
+  node.kind = kind;
+  for (;;) {
+    var decl = this$1.startNode();
+    this$1.parseVarId(decl, kind);
+    if (this$1.eat(types.eq)) {
+      decl.init = this$1.parseMaybeAssign(isFor);
+    } else if (kind === "const" && !(this$1.type === types._in || (this$1.options.ecmaVersion >= 6 && this$1.isContextual("of")))) {
+      this$1.unexpected();
+    } else if (decl.id.type != "Identifier" && !(isFor && (this$1.type === types._in || this$1.isContextual("of")))) {
+      this$1.raise(this$1.lastTokEnd, "Complex binding patterns require an initialization value");
+    } else {
+      decl.init = null;
+    }
+    node.declarations.push(this$1.finishNode(decl, "VariableDeclarator"));
+    if (!this$1.eat(types.comma)) { break }
+  }
+  return node
+};
+
+pp$1.parseVarId = function(decl, kind) {
+  decl.id = this.parseBindingAtom(kind);
+  this.checkLVal(decl.id, kind, false);
+};
+
+// Parse a function declaration or literal (depending on the
+// `isStatement` parameter).
+
+pp$1.parseFunction = function(node, isStatement, allowExpressionBody, isAsync) {
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 6 && !isAsync)
+    { node.generator = this.eat(types.star); }
+  if (this.options.ecmaVersion >= 8)
+    { node.async = !!isAsync; }
+
+  if (isStatement) {
+    node.id = isStatement === "nullableID" && this.type != types.name ? null : this.parseIdent();
+    if (node.id) {
+      this.checkLVal(node.id, "var");
+    }
+  }
+
+  var oldInGen = this.inGenerator, oldInAsync = this.inAsync,
+      oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos, oldInFunc = this.inFunction;
+  this.inGenerator = node.generator;
+  this.inAsync = node.async;
+  this.yieldPos = 0;
+  this.awaitPos = 0;
+  this.inFunction = true;
+  this.enterFunctionScope();
+
+  if (!isStatement)
+    { node.id = this.type == types.name ? this.parseIdent() : null; }
+
+  this.parseFunctionParams(node);
+  this.parseFunctionBody(node, allowExpressionBody);
+
+  this.inGenerator = oldInGen;
+  this.inAsync = oldInAsync;
+  this.yieldPos = oldYieldPos;
+  this.awaitPos = oldAwaitPos;
+  this.inFunction = oldInFunc;
+  return this.finishNode(node, isStatement ? "FunctionDeclaration" : "FunctionExpression")
+};
+
+pp$1.parseFunctionParams = function(node) {
+  this.expect(types.parenL);
+  node.params = this.parseBindingList(types.parenR, false, this.options.ecmaVersion >= 8);
+  this.checkYieldAwaitInDefaultParams();
+};
+
+// Parse a class declaration or literal (depending on the
+// `isStatement` parameter).
+
+pp$1.parseClass = function(node, isStatement) {
+  var this$1 = this;
+
+  this.next();
+
+  this.parseClassId(node, isStatement);
+  this.parseClassSuper(node);
+  var classBody = this.startNode();
+  var hadConstructor = false;
+  classBody.body = [];
+  this.expect(types.braceL);
+  while (!this.eat(types.braceR)) {
+    if (this$1.eat(types.semi)) { continue }
+    var method = this$1.startNode();
+    var isGenerator = this$1.eat(types.star);
+    var isAsync = false;
+    var isMaybeStatic = this$1.type === types.name && this$1.value === "static";
+    this$1.parsePropertyName(method);
+    method.static = isMaybeStatic && this$1.type !== types.parenL;
+    if (method.static) {
+      if (isGenerator) { this$1.unexpected(); }
+      isGenerator = this$1.eat(types.star);
+      this$1.parsePropertyName(method);
+    }
+    if (this$1.options.ecmaVersion >= 8 && !isGenerator && !method.computed &&
+        method.key.type === "Identifier" && method.key.name === "async" && this$1.type !== types.parenL &&
+        !this$1.canInsertSemicolon()) {
+      isAsync = true;
+      this$1.parsePropertyName(method);
+    }
+    method.kind = "method";
+    var isGetSet = false;
+    if (!method.computed) {
+      var key = method.key;
+      if (!isGenerator && !isAsync && key.type === "Identifier" && this$1.type !== types.parenL && (key.name === "get" || key.name === "set")) {
+        isGetSet = true;
+        method.kind = key.name;
+        key = this$1.parsePropertyName(method);
+      }
+      if (!method.static && (key.type === "Identifier" && key.name === "constructor" ||
+          key.type === "Literal" && key.value === "constructor")) {
+        if (hadConstructor) { this$1.raise(key.start, "Duplicate constructor in the same class"); }
+        if (isGetSet) { this$1.raise(key.start, "Constructor can't have get/set modifier"); }
+        if (isGenerator) { this$1.raise(key.start, "Constructor can't be a generator"); }
+        if (isAsync) { this$1.raise(key.start, "Constructor can't be an async method"); }
+        method.kind = "constructor";
+        hadConstructor = true;
+      }
+    }
+    this$1.parseClassMethod(classBody, method, isGenerator, isAsync);
+    if (isGetSet) {
+      var paramCount = method.kind === "get" ? 0 : 1;
+      if (method.value.params.length !== paramCount) {
+        var start = method.value.start;
+        if (method.kind === "get")
+          { this$1.raiseRecoverable(start, "getter should have no params"); }
+        else
+          { this$1.raiseRecoverable(start, "setter should have exactly one param"); }
+      } else {
+        if (method.kind === "set" && method.value.params[0].type === "RestElement")
+          { this$1.raiseRecoverable(method.value.params[0].start, "Setter cannot use rest params"); }
+      }
+    }
+  }
+  node.body = this.finishNode(classBody, "ClassBody");
+  return this.finishNode(node, isStatement ? "ClassDeclaration" : "ClassExpression")
+};
+
+pp$1.parseClassMethod = function(classBody, method, isGenerator, isAsync) {
+  method.value = this.parseMethod(isGenerator, isAsync);
+  classBody.body.push(this.finishNode(method, "MethodDefinition"));
+};
+
+pp$1.parseClassId = function(node, isStatement) {
+  node.id = this.type === types.name ? this.parseIdent() : isStatement === true ? this.unexpected() : null;
+};
+
+pp$1.parseClassSuper = function(node) {
+  node.superClass = this.eat(types._extends) ? this.parseExprSubscripts() : null;
+};
+
+// Parses module export declaration.
+
+pp$1.parseExport = function(node, exports) {
+  var this$1 = this;
+
+  this.next();
+  // export * from '...'
+  if (this.eat(types.star)) {
+    this.expectContextual("from");
+    node.source = this.type === types.string ? this.parseExprAtom() : this.unexpected();
+    this.semicolon();
+    return this.finishNode(node, "ExportAllDeclaration")
+  }
+  if (this.eat(types._default)) { // export default ...
+    this.checkExport(exports, "default", this.lastTokStart);
+    var isAsync;
+    if (this.type === types._function || (isAsync = this.isAsyncFunction())) {
+      var fNode = this.startNode();
+      this.next();
+      if (isAsync) { this.next(); }
+      node.declaration = this.parseFunction(fNode, "nullableID", false, isAsync);
+    } else if (this.type === types._class) {
+      var cNode = this.startNode();
+      node.declaration = this.parseClass(cNode, "nullableID");
+    } else {
+      node.declaration = this.parseMaybeAssign();
+      this.semicolon();
+    }
+    return this.finishNode(node, "ExportDefaultDeclaration")
+  }
+  // export var|const|let|function|class ...
+  if (this.shouldParseExportStatement()) {
+    node.declaration = this.parseStatement(true);
+    if (node.declaration.type === "VariableDeclaration")
+      { this.checkVariableExport(exports, node.declaration.declarations); }
+    else
+      { this.checkExport(exports, node.declaration.id.name, node.declaration.id.start); }
+    node.specifiers = [];
+    node.source = null;
+  } else { // export { x, y as z } [from '...']
+    node.declaration = null;
+    node.specifiers = this.parseExportSpecifiers(exports);
+    if (this.eatContextual("from")) {
+      node.source = this.type === types.string ? this.parseExprAtom() : this.unexpected();
+    } else {
+      // check for keywords used as local names
+      for (var i = 0, list = node.specifiers; i < list.length; i += 1) {
+        var spec = list[i];
+
+        this$1.checkUnreserved(spec.local);
+      }
+
+      node.source = null;
+    }
+    this.semicolon();
+  }
+  return this.finishNode(node, "ExportNamedDeclaration")
+};
+
+pp$1.checkExport = function(exports, name, pos) {
+  if (!exports) { return }
+  if (has(exports, name))
+    { this.raiseRecoverable(pos, "Duplicate export '" + name + "'"); }
+  exports[name] = true;
+};
+
+pp$1.checkPatternExport = function(exports, pat) {
+  var this$1 = this;
+
+  var type = pat.type;
+  if (type == "Identifier")
+    { this.checkExport(exports, pat.name, pat.start); }
+  else if (type == "ObjectPattern")
+    { for (var i = 0, list = pat.properties; i < list.length; i += 1)
+      {
+        var prop = list[i];
+
+        this$1.checkPatternExport(exports, prop.value);
+      } }
+  else if (type == "ArrayPattern")
+    { for (var i$1 = 0, list$1 = pat.elements; i$1 < list$1.length; i$1 += 1) {
+      var elt = list$1[i$1];
+
+        if (elt) { this$1.checkPatternExport(exports, elt); }
+    } }
+  else if (type == "AssignmentPattern")
+    { this.checkPatternExport(exports, pat.left); }
+  else if (type == "ParenthesizedExpression")
+    { this.checkPatternExport(exports, pat.expression); }
+};
+
+pp$1.checkVariableExport = function(exports, decls) {
+  var this$1 = this;
+
+  if (!exports) { return }
+  for (var i = 0, list = decls; i < list.length; i += 1)
+    {
+    var decl = list[i];
+
+    this$1.checkPatternExport(exports, decl.id);
+  }
+};
+
+pp$1.shouldParseExportStatement = function() {
+  return this.type.keyword === "var" ||
+    this.type.keyword === "const" ||
+    this.type.keyword === "class" ||
+    this.type.keyword === "function" ||
+    this.isLet() ||
+    this.isAsyncFunction()
+};
+
+// Parses a comma-separated list of module exports.
+
+pp$1.parseExportSpecifiers = function(exports) {
+  var this$1 = this;
+
+  var nodes = [], first = true;
+  // export { x, y as z } [from '...']
+  this.expect(types.braceL);
+  while (!this.eat(types.braceR)) {
+    if (!first) {
+      this$1.expect(types.comma);
+      if (this$1.afterTrailingComma(types.braceR)) { break }
+    } else { first = false; }
+
+    var node = this$1.startNode();
+    node.local = this$1.parseIdent(true);
+    node.exported = this$1.eatContextual("as") ? this$1.parseIdent(true) : node.local;
+    this$1.checkExport(exports, node.exported.name, node.exported.start);
+    nodes.push(this$1.finishNode(node, "ExportSpecifier"));
+  }
+  return nodes
+};
+
+// Parses import declaration.
+
+pp$1.parseImport = function(node) {
+  this.next();
+  // import '...'
+  if (this.type === types.string) {
+    node.specifiers = empty;
+    node.source = this.parseExprAtom();
+  } else {
+    node.specifiers = this.parseImportSpecifiers();
+    this.expectContextual("from");
+    node.source = this.type === types.string ? this.parseExprAtom() : this.unexpected();
+  }
+  this.semicolon();
+  return this.finishNode(node, "ImportDeclaration")
+};
+
+// Parses a comma-separated list of module imports.
+
+pp$1.parseImportSpecifiers = function() {
+  var this$1 = this;
+
+  var nodes = [], first = true;
+  if (this.type === types.name) {
+    // import defaultObj, { x, y as z } from '...'
+    var node = this.startNode();
+    node.local = this.parseIdent();
+    this.checkLVal(node.local, "let");
+    nodes.push(this.finishNode(node, "ImportDefaultSpecifier"));
+    if (!this.eat(types.comma)) { return nodes }
+  }
+  if (this.type === types.star) {
+    var node$1 = this.startNode();
+    this.next();
+    this.expectContextual("as");
+    node$1.local = this.parseIdent();
+    this.checkLVal(node$1.local, "let");
+    nodes.push(this.finishNode(node$1, "ImportNamespaceSpecifier"));
+    return nodes
+  }
+  this.expect(types.braceL);
+  while (!this.eat(types.braceR)) {
+    if (!first) {
+      this$1.expect(types.comma);
+      if (this$1.afterTrailingComma(types.braceR)) { break }
+    } else { first = false; }
+
+    var node$2 = this$1.startNode();
+    node$2.imported = this$1.parseIdent(true);
+    if (this$1.eatContextual("as")) {
+      node$2.local = this$1.parseIdent();
+    } else {
+      this$1.checkUnreserved(node$2.imported);
+      node$2.local = node$2.imported;
+    }
+    this$1.checkLVal(node$2.local, "let");
+    nodes.push(this$1.finishNode(node$2, "ImportSpecifier"));
+  }
+  return nodes
+};
+
+// Set `ExpressionStatement#directive` property for directive prologues.
+pp$1.adaptDirectivePrologue = function(statements) {
+  for (var i = 0; i < statements.length && this.isDirectiveCandidate(statements[i]); ++i) {
+    statements[i].directive = statements[i].expression.raw.slice(1, -1);
+  }
+};
+pp$1.isDirectiveCandidate = function(statement) {
+  return (
+    statement.type === "ExpressionStatement" &&
+    statement.expression.type === "Literal" &&
+    typeof statement.expression.value === "string" &&
+    // Reject parenthesized strings.
+    (this.input[statement.start] === "\"" || this.input[statement.start] === "'")
+  )
+};
+
+var pp$2 = Parser.prototype;
+
+// Convert existing expression atom to assignable pattern
+// if possible.
+
+pp$2.toAssignable = function(node, isBinding) {
+  var this$1 = this;
+
+  if (this.options.ecmaVersion >= 6 && node) {
+    switch (node.type) {
+    case "Identifier":
+      if (this.inAsync && node.name === "await")
+        { this.raise(node.start, "Can not use 'await' as identifier inside an async function"); }
+      break
+
+    case "ObjectPattern":
+    case "ArrayPattern":
+      break
+
+    case "ObjectExpression":
+      node.type = "ObjectPattern";
+      for (var i = 0, list = node.properties; i < list.length; i += 1) {
+        var prop = list[i];
+
+      if (prop.kind !== "init") { this$1.raise(prop.key.start, "Object pattern can't contain getter or setter"); }
+        this$1.toAssignable(prop.value, isBinding);
+      }
+      break
+
+    case "ArrayExpression":
+      node.type = "ArrayPattern";
+      this.toAssignableList(node.elements, isBinding);
+      break
+
+    case "AssignmentExpression":
+      if (node.operator === "=") {
+        node.type = "AssignmentPattern";
+        delete node.operator;
+        this.toAssignable(node.left, isBinding);
+        // falls through to AssignmentPattern
+      } else {
+        this.raise(node.left.end, "Only '=' operator can be used for specifying default value.");
+        break
+      }
+
+    case "AssignmentPattern":
+      break
+
+    case "ParenthesizedExpression":
+      this.toAssignable(node.expression, isBinding);
+      break
+
+    case "MemberExpression":
+      if (!isBinding) { break }
+
+    default:
+      this.raise(node.start, "Assigning to rvalue");
+    }
+  }
+  return node
+};
+
+// Convert list of expression atoms to binding list.
+
+pp$2.toAssignableList = function(exprList, isBinding) {
+  var this$1 = this;
+
+  var end = exprList.length;
+  if (end) {
+    var last = exprList[end - 1];
+    if (last && last.type == "RestElement") {
+      --end;
+    } else if (last && last.type == "SpreadElement") {
+      last.type = "RestElement";
+      var arg = last.argument;
+      this.toAssignable(arg, isBinding);
+      --end;
+    }
+
+    if (this.options.ecmaVersion === 6 && isBinding && last && last.type === "RestElement" && last.argument.type !== "Identifier")
+      { this.unexpected(last.argument.start); }
+  }
+  for (var i = 0; i < end; i++) {
+    var elt = exprList[i];
+    if (elt) { this$1.toAssignable(elt, isBinding); }
+  }
+  return exprList
+};
+
+// Parses spread element.
+
+pp$2.parseSpread = function(refDestructuringErrors) {
+  var node = this.startNode();
+  this.next();
+  node.argument = this.parseMaybeAssign(false, refDestructuringErrors);
+  return this.finishNode(node, "SpreadElement")
+};
+
+pp$2.parseRestBinding = function() {
+  var node = this.startNode();
+  this.next();
+
+  // RestElement inside of a function parameter must be an identifier
+  if (this.options.ecmaVersion === 6 && this.type !== types.name)
+    { this.unexpected(); }
+
+  node.argument = this.parseBindingAtom();
+
+  return this.finishNode(node, "RestElement")
+};
+
+// Parses lvalue (assignable) atom.
+
+pp$2.parseBindingAtom = function() {
+  if (this.options.ecmaVersion >= 6) {
+    switch (this.type) {
+    case types.bracketL:
+      var node = this.startNode();
+      this.next();
+      node.elements = this.parseBindingList(types.bracketR, true, true);
+      return this.finishNode(node, "ArrayPattern")
+
+    case types.braceL:
+      return this.parseObj(true)
+    }
+  }
+  return this.parseIdent()
+};
+
+pp$2.parseBindingList = function(close, allowEmpty, allowTrailingComma) {
+  var this$1 = this;
+
+  var elts = [], first = true;
+  while (!this.eat(close)) {
+    if (first) { first = false; }
+    else { this$1.expect(types.comma); }
+    if (allowEmpty && this$1.type === types.comma) {
+      elts.push(null);
+    } else if (allowTrailingComma && this$1.afterTrailingComma(close)) {
+      break
+    } else if (this$1.type === types.ellipsis) {
+      var rest = this$1.parseRestBinding();
+      this$1.parseBindingListItem(rest);
+      elts.push(rest);
+      if (this$1.type === types.comma) { this$1.raise(this$1.start, "Comma is not permitted after the rest element"); }
+      this$1.expect(close);
+      break
+    } else {
+      var elem = this$1.parseMaybeDefault(this$1.start, this$1.startLoc);
+      this$1.parseBindingListItem(elem);
+      elts.push(elem);
+    }
+  }
+  return elts
+};
+
+pp$2.parseBindingListItem = function(param) {
+  return param
+};
+
+// Parses assignment pattern around given atom if possible.
+
+pp$2.parseMaybeDefault = function(startPos, startLoc, left) {
+  left = left || this.parseBindingAtom();
+  if (this.options.ecmaVersion < 6 || !this.eat(types.eq)) { return left }
+  var node = this.startNodeAt(startPos, startLoc);
+  node.left = left;
+  node.right = this.parseMaybeAssign();
+  return this.finishNode(node, "AssignmentPattern")
+};
+
+// Verify that a node is an lval — something that can be assigned
+// to.
+// bindingType can be either:
+// 'var' indicating that the lval creates a 'var' binding
+// 'let' indicating that the lval creates a lexical ('let' or 'const') binding
+// 'none' indicating that the binding should be checked for illegal identifiers, but not for duplicate references
+
+pp$2.checkLVal = function(expr, bindingType, checkClashes) {
+  var this$1 = this;
+
+  switch (expr.type) {
+  case "Identifier":
+    if (this.strict && this.reservedWordsStrictBind.test(expr.name))
+      { this.raiseRecoverable(expr.start, (bindingType ? "Binding " : "Assigning to ") + expr.name + " in strict mode"); }
+    if (checkClashes) {
+      if (has(checkClashes, expr.name))
+        { this.raiseRecoverable(expr.start, "Argument name clash"); }
+      checkClashes[expr.name] = true;
+    }
+    if (bindingType && bindingType !== "none") {
+      if (
+        bindingType === "var" && !this.canDeclareVarName(expr.name) ||
+        bindingType !== "var" && !this.canDeclareLexicalName(expr.name)
+      ) {
+        this.raiseRecoverable(expr.start, ("Identifier '" + (expr.name) + "' has already been declared"));
+      }
+      if (bindingType === "var") {
+        this.declareVarName(expr.name);
+      } else {
+        this.declareLexicalName(expr.name);
+      }
+    }
+    break
+
+  case "MemberExpression":
+    if (bindingType) { this.raiseRecoverable(expr.start, (bindingType ? "Binding" : "Assigning to") + " member expression"); }
+    break
+
+  case "ObjectPattern":
+    for (var i = 0, list = expr.properties; i < list.length; i += 1)
+      {
+    var prop = list[i];
+
+    this$1.checkLVal(prop.value, bindingType, checkClashes);
+  }
+    break
+
+  case "ArrayPattern":
+    for (var i$1 = 0, list$1 = expr.elements; i$1 < list$1.length; i$1 += 1) {
+      var elem = list$1[i$1];
+
+    if (elem) { this$1.checkLVal(elem, bindingType, checkClashes); }
+    }
+    break
+
+  case "AssignmentPattern":
+    this.checkLVal(expr.left, bindingType, checkClashes);
+    break
+
+  case "RestElement":
+    this.checkLVal(expr.argument, bindingType, checkClashes);
+    break
+
+  case "ParenthesizedExpression":
+    this.checkLVal(expr.expression, bindingType, checkClashes);
+    break
+
+  default:
+    this.raise(expr.start, (bindingType ? "Binding" : "Assigning to") + " rvalue");
+  }
+};
+
+// A recursive descent parser operates by defining functions for all
+// syntactic elements, and recursively calling those, each function
+// advancing the input stream and returning an AST node. Precedence
+// of constructs (for example, the fact that `!x[1]` means `!(x[1])`
+// instead of `(!x)[1]` is handled by the fact that the parser
+// function that parses unary prefix operators is called first, and
+// in turn calls the function that parses `[]` subscripts — that
+// way, it'll receive the node for `x[1]` already parsed, and wraps
+// *that* in the unary operator node.
+//
+// Acorn uses an [operator precedence parser][opp] to handle binary
+// operator precedence, because it is much more compact than using
+// the technique outlined above, which uses different, nesting
+// functions to specify precedence, for all of the ten binary
+// precedence levels that JavaScript defines.
+//
+// [opp]: http://en.wikipedia.org/wiki/Operator-precedence_parser
+
+var pp$3 = Parser.prototype;
+
+// Check if property name clashes with already added.
+// Object/class getters and setters are not allowed to clash —
+// either with each other or with an init property — and in
+// strict mode, init properties are also not allowed to be repeated.
+
+pp$3.checkPropClash = function(prop, propHash) {
+  if (this.options.ecmaVersion >= 6 && (prop.computed || prop.method || prop.shorthand))
+    { return }
+  var key = prop.key;
+  var name;
+  switch (key.type) {
+  case "Identifier": name = key.name; break
+  case "Literal": name = String(key.value); break
+  default: return
+  }
+  var kind = prop.kind;
+  if (this.options.ecmaVersion >= 6) {
+    if (name === "__proto__" && kind === "init") {
+      if (propHash.proto) { this.raiseRecoverable(key.start, "Redefinition of __proto__ property"); }
+      propHash.proto = true;
+    }
+    return
+  }
+  name = "$" + name;
+  var other = propHash[name];
+  if (other) {
+    var redefinition;
+    if (kind === "init") {
+      redefinition = this.strict && other.init || other.get || other.set;
+    } else {
+      redefinition = other.init || other[kind];
+    }
+    if (redefinition)
+      { this.raiseRecoverable(key.start, "Redefinition of property"); }
+  } else {
+    other = propHash[name] = {
+      init: false,
+      get: false,
+      set: false
+    };
+  }
+  other[kind] = true;
+};
+
+// ### Expression parsing
+
+// These nest, from the most general expression type at the top to
+// 'atomic', nondivisible expression types at the bottom. Most of
+// the functions will simply let the function(s) below them parse,
+// and, *if* the syntactic construct they handle is present, wrap
+// the AST node that the inner parser gave them in another node.
+
+// Parse a full expression. The optional arguments are used to
+// forbid the `in` operator (in for loops initalization expressions)
+// and provide reference for storing '=' operator inside shorthand
+// property assignment in contexts where both object expression
+// and object pattern might appear (so it's possible to raise
+// delayed syntax error at correct position).
+
+pp$3.parseExpression = function(noIn, refDestructuringErrors) {
+  var this$1 = this;
+
+  var startPos = this.start, startLoc = this.startLoc;
+  var expr = this.parseMaybeAssign(noIn, refDestructuringErrors);
+  if (this.type === types.comma) {
+    var node = this.startNodeAt(startPos, startLoc);
+    node.expressions = [expr];
+    while (this.eat(types.comma)) { node.expressions.push(this$1.parseMaybeAssign(noIn, refDestructuringErrors)); }
+    return this.finishNode(node, "SequenceExpression")
+  }
+  return expr
+};
+
+// Parse an assignment expression. This includes applications of
+// operators like `+=`.
+
+pp$3.parseMaybeAssign = function(noIn, refDestructuringErrors, afterLeftParse) {
+  if (this.inGenerator && this.isContextual("yield")) { return this.parseYield() }
+
+  var ownDestructuringErrors = false, oldParenAssign = -1, oldTrailingComma = -1;
+  if (refDestructuringErrors) {
+    oldParenAssign = refDestructuringErrors.parenthesizedAssign;
+    oldTrailingComma = refDestructuringErrors.trailingComma;
+    refDestructuringErrors.parenthesizedAssign = refDestructuringErrors.trailingComma = -1;
+  } else {
+    refDestructuringErrors = new DestructuringErrors;
+    ownDestructuringErrors = true;
+  }
+
+  var startPos = this.start, startLoc = this.startLoc;
+  if (this.type == types.parenL || this.type == types.name)
+    { this.potentialArrowAt = this.start; }
+  var left = this.parseMaybeConditional(noIn, refDestructuringErrors);
+  if (afterLeftParse) { left = afterLeftParse.call(this, left, startPos, startLoc); }
+  if (this.type.isAssign) {
+    this.checkPatternErrors(refDestructuringErrors, true);
+    if (!ownDestructuringErrors) { DestructuringErrors.call(refDestructuringErrors); }
+    var node = this.startNodeAt(startPos, startLoc);
+    node.operator = this.value;
+    node.left = this.type === types.eq ? this.toAssignable(left) : left;
+    refDestructuringErrors.shorthandAssign = -1; // reset because shorthand default was used correctly
+    this.checkLVal(left);
+    this.next();
+    node.right = this.parseMaybeAssign(noIn);
+    return this.finishNode(node, "AssignmentExpression")
+  } else {
+    if (ownDestructuringErrors) { this.checkExpressionErrors(refDestructuringErrors, true); }
+  }
+  if (oldParenAssign > -1) { refDestructuringErrors.parenthesizedAssign = oldParenAssign; }
+  if (oldTrailingComma > -1) { refDestructuringErrors.trailingComma = oldTrailingComma; }
+  return left
+};
+
+// Parse a ternary conditional (`?:`) operator.
+
+pp$3.parseMaybeConditional = function(noIn, refDestructuringErrors) {
+  var startPos = this.start, startLoc = this.startLoc;
+  var expr = this.parseExprOps(noIn, refDestructuringErrors);
+  if (this.checkExpressionErrors(refDestructuringErrors)) { return expr }
+  if (this.eat(types.question)) {
+    var node = this.startNodeAt(startPos, startLoc);
+    node.test = expr;
+    node.consequent = this.parseMaybeAssign();
+    this.expect(types.colon);
+    node.alternate = this.parseMaybeAssign(noIn);
+    return this.finishNode(node, "ConditionalExpression")
+  }
+  return expr
+};
+
+// Start the precedence parser.
+
+pp$3.parseExprOps = function(noIn, refDestructuringErrors) {
+  var startPos = this.start, startLoc = this.startLoc;
+  var expr = this.parseMaybeUnary(refDestructuringErrors, false);
+  if (this.checkExpressionErrors(refDestructuringErrors)) { return expr }
+  return expr.start == startPos && expr.type === "ArrowFunctionExpression" ? expr : this.parseExprOp(expr, startPos, startLoc, -1, noIn)
+};
+
+// Parse binary operators with the operator precedence parsing
+// algorithm. `left` is the left-hand side of the operator.
+// `minPrec` provides context that allows the function to stop and
+// defer further parser to one of its callers when it encounters an
+// operator that has a lower precedence than the set it is parsing.
+
+pp$3.parseExprOp = function(left, leftStartPos, leftStartLoc, minPrec, noIn) {
+  var prec = this.type.binop;
+  if (prec != null && (!noIn || this.type !== types._in)) {
+    if (prec > minPrec) {
+      var logical = this.type === types.logicalOR || this.type === types.logicalAND;
+      var op = this.value;
+      this.next();
+      var startPos = this.start, startLoc = this.startLoc;
+      var right = this.parseExprOp(this.parseMaybeUnary(null, false), startPos, startLoc, prec, noIn);
+      var node = this.buildBinary(leftStartPos, leftStartLoc, left, right, op, logical);
+      return this.parseExprOp(node, leftStartPos, leftStartLoc, minPrec, noIn)
+    }
+  }
+  return left
+};
+
+pp$3.buildBinary = function(startPos, startLoc, left, right, op, logical) {
+  var node = this.startNodeAt(startPos, startLoc);
+  node.left = left;
+  node.operator = op;
+  node.right = right;
+  return this.finishNode(node, logical ? "LogicalExpression" : "BinaryExpression")
+};
+
+// Parse unary operators, both prefix and postfix.
+
+pp$3.parseMaybeUnary = function(refDestructuringErrors, sawUnary) {
+  var this$1 = this;
+
+  var startPos = this.start, startLoc = this.startLoc, expr;
+  if (this.inAsync && this.isContextual("await")) {
+    expr = this.parseAwait();
+    sawUnary = true;
+  } else if (this.type.prefix) {
+    var node = this.startNode(), update = this.type === types.incDec;
+    node.operator = this.value;
+    node.prefix = true;
+    this.next();
+    node.argument = this.parseMaybeUnary(null, true);
+    this.checkExpressionErrors(refDestructuringErrors, true);
+    if (update) { this.checkLVal(node.argument); }
+    else if (this.strict && node.operator === "delete" &&
+             node.argument.type === "Identifier")
+      { this.raiseRecoverable(node.start, "Deleting local variable in strict mode"); }
+    else { sawUnary = true; }
+    expr = this.finishNode(node, update ? "UpdateExpression" : "UnaryExpression");
+  } else {
+    expr = this.parseExprSubscripts(refDestructuringErrors);
+    if (this.checkExpressionErrors(refDestructuringErrors)) { return expr }
+    while (this.type.postfix && !this.canInsertSemicolon()) {
+      var node$1 = this$1.startNodeAt(startPos, startLoc);
+      node$1.operator = this$1.value;
+      node$1.prefix = false;
+      node$1.argument = expr;
+      this$1.checkLVal(expr);
+      this$1.next();
+      expr = this$1.finishNode(node$1, "UpdateExpression");
+    }
+  }
+
+  if (!sawUnary && this.eat(types.starstar))
+    { return this.buildBinary(startPos, startLoc, expr, this.parseMaybeUnary(null, false), "**", false) }
+  else
+    { return expr }
+};
+
+// Parse call, dot, and `[]`-subscript expressions.
+
+pp$3.parseExprSubscripts = function(refDestructuringErrors) {
+  var startPos = this.start, startLoc = this.startLoc;
+  var expr = this.parseExprAtom(refDestructuringErrors);
+  var skipArrowSubscripts = expr.type === "ArrowFunctionExpression" && this.input.slice(this.lastTokStart, this.lastTokEnd) !== ")";
+  if (this.checkExpressionErrors(refDestructuringErrors) || skipArrowSubscripts) { return expr }
+  var result = this.parseSubscripts(expr, startPos, startLoc);
+  if (refDestructuringErrors && result.type === "MemberExpression") {
+    if (refDestructuringErrors.parenthesizedAssign >= result.start) { refDestructuringErrors.parenthesizedAssign = -1; }
+    if (refDestructuringErrors.parenthesizedBind >= result.start) { refDestructuringErrors.parenthesizedBind = -1; }
+  }
+  return result
+};
+
+pp$3.parseSubscripts = function(base, startPos, startLoc, noCalls) {
+  var this$1 = this;
+
+  var maybeAsyncArrow = this.options.ecmaVersion >= 8 && base.type === "Identifier" && base.name === "async" &&
+      this.lastTokEnd == base.end && !this.canInsertSemicolon();
+  for (var computed = (void 0);;) {
+    if ((computed = this$1.eat(types.bracketL)) || this$1.eat(types.dot)) {
+      var node = this$1.startNodeAt(startPos, startLoc);
+      node.object = base;
+      node.property = computed ? this$1.parseExpression() : this$1.parseIdent(true);
+      node.computed = !!computed;
+      if (computed) { this$1.expect(types.bracketR); }
+      base = this$1.finishNode(node, "MemberExpression");
+    } else if (!noCalls && this$1.eat(types.parenL)) {
+      var refDestructuringErrors = new DestructuringErrors, oldYieldPos = this$1.yieldPos, oldAwaitPos = this$1.awaitPos;
+      this$1.yieldPos = 0;
+      this$1.awaitPos = 0;
+      var exprList = this$1.parseExprList(types.parenR, this$1.options.ecmaVersion >= 8, false, refDestructuringErrors);
+      if (maybeAsyncArrow && !this$1.canInsertSemicolon() && this$1.eat(types.arrow)) {
+        this$1.checkPatternErrors(refDestructuringErrors, false);
+        this$1.checkYieldAwaitInDefaultParams();
+        this$1.yieldPos = oldYieldPos;
+        this$1.awaitPos = oldAwaitPos;
+        return this$1.parseArrowExpression(this$1.startNodeAt(startPos, startLoc), exprList, true)
+      }
+      this$1.checkExpressionErrors(refDestructuringErrors, true);
+      this$1.yieldPos = oldYieldPos || this$1.yieldPos;
+      this$1.awaitPos = oldAwaitPos || this$1.awaitPos;
+      var node$1 = this$1.startNodeAt(startPos, startLoc);
+      node$1.callee = base;
+      node$1.arguments = exprList;
+      base = this$1.finishNode(node$1, "CallExpression");
+    } else if (this$1.type === types.backQuote) {
+      var node$2 = this$1.startNodeAt(startPos, startLoc);
+      node$2.tag = base;
+      node$2.quasi = this$1.parseTemplate({isTagged: true});
+      base = this$1.finishNode(node$2, "TaggedTemplateExpression");
+    } else {
+      return base
+    }
+  }
+};
+
+// Parse an atomic expression — either a single token that is an
+// expression, an expression started by a keyword like `function` or
+// `new`, or an expression wrapped in punctuation like `()`, `[]`,
+// or `{}`.
+
+pp$3.parseExprAtom = function(refDestructuringErrors) {
+  var node, canBeArrow = this.potentialArrowAt == this.start;
+  switch (this.type) {
+  case types._super:
+    if (!this.inFunction)
+      { this.raise(this.start, "'super' outside of function or class"); }
+    node = this.startNode();
+    this.next();
+    // The `super` keyword can appear at below:
+    // SuperProperty:
+    //     super [ Expression ]
+    //     super . IdentifierName
+    // SuperCall:
+    //     super Arguments
+    if (this.type !== types.dot && this.type !== types.bracketL && this.type !== types.parenL)
+      { this.unexpected(); }
+    return this.finishNode(node, "Super")
+
+  case types._this:
+    node = this.startNode();
+    this.next();
+    return this.finishNode(node, "ThisExpression")
+
+  case types.name:
+    var startPos = this.start, startLoc = this.startLoc;
+    var id = this.parseIdent(this.type !== types.name);
+    if (this.options.ecmaVersion >= 8 && id.name === "async" && !this.canInsertSemicolon() && this.eat(types._function))
+      { return this.parseFunction(this.startNodeAt(startPos, startLoc), false, false, true) }
+    if (canBeArrow && !this.canInsertSemicolon()) {
+      if (this.eat(types.arrow))
+        { return this.parseArrowExpression(this.startNodeAt(startPos, startLoc), [id], false) }
+      if (this.options.ecmaVersion >= 8 && id.name === "async" && this.type === types.name) {
+        id = this.parseIdent();
+        if (this.canInsertSemicolon() || !this.eat(types.arrow))
+          { this.unexpected(); }
+        return this.parseArrowExpression(this.startNodeAt(startPos, startLoc), [id], true)
+      }
+    }
+    return id
+
+  case types.regexp:
+    var value = this.value;
+    node = this.parseLiteral(value.value);
+    node.regex = {pattern: value.pattern, flags: value.flags};
+    return node
+
+  case types.num: case types.string:
+    return this.parseLiteral(this.value)
+
+  case types._null: case types._true: case types._false:
+    node = this.startNode();
+    node.value = this.type === types._null ? null : this.type === types._true;
+    node.raw = this.type.keyword;
+    this.next();
+    return this.finishNode(node, "Literal")
+
+  case types.parenL:
+    var start = this.start, expr = this.parseParenAndDistinguishExpression(canBeArrow);
+    if (refDestructuringErrors) {
+      if (refDestructuringErrors.parenthesizedAssign < 0 && !this.isSimpleAssignTarget(expr))
+        { refDestructuringErrors.parenthesizedAssign = start; }
+      if (refDestructuringErrors.parenthesizedBind < 0)
+        { refDestructuringErrors.parenthesizedBind = start; }
+    }
+    return expr
+
+  case types.bracketL:
+    node = this.startNode();
+    this.next();
+    node.elements = this.parseExprList(types.bracketR, true, true, refDestructuringErrors);
+    return this.finishNode(node, "ArrayExpression")
+
+  case types.braceL:
+    return this.parseObj(false, refDestructuringErrors)
+
+  case types._function:
+    node = this.startNode();
+    this.next();
+    return this.parseFunction(node, false)
+
+  case types._class:
+    return this.parseClass(this.startNode(), false)
+
+  case types._new:
+    return this.parseNew()
+
+  case types.backQuote:
+    return this.parseTemplate()
+
+  default:
+    this.unexpected();
+  }
+};
+
+pp$3.parseLiteral = function(value) {
+  var node = this.startNode();
+  node.value = value;
+  node.raw = this.input.slice(this.start, this.end);
+  this.next();
+  return this.finishNode(node, "Literal")
+};
+
+pp$3.parseParenExpression = function() {
+  this.expect(types.parenL);
+  var val = this.parseExpression();
+  this.expect(types.parenR);
+  return val
+};
+
+pp$3.parseParenAndDistinguishExpression = function(canBeArrow) {
+  var this$1 = this;
+
+  var startPos = this.start, startLoc = this.startLoc, val, allowTrailingComma = this.options.ecmaVersion >= 8;
+  if (this.options.ecmaVersion >= 6) {
+    this.next();
+
+    var innerStartPos = this.start, innerStartLoc = this.startLoc;
+    var exprList = [], first = true, lastIsComma = false;
+    var refDestructuringErrors = new DestructuringErrors, oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos, spreadStart, innerParenStart;
+    this.yieldPos = 0;
+    this.awaitPos = 0;
+    while (this.type !== types.parenR) {
+      first ? first = false : this$1.expect(types.comma);
+      if (allowTrailingComma && this$1.afterTrailingComma(types.parenR, true)) {
+        lastIsComma = true;
+        break
+      } else if (this$1.type === types.ellipsis) {
+        spreadStart = this$1.start;
+        exprList.push(this$1.parseParenItem(this$1.parseRestBinding()));
+        if (this$1.type === types.comma) { this$1.raise(this$1.start, "Comma is not permitted after the rest element"); }
+        break
+      } else {
+        if (this$1.type === types.parenL && !innerParenStart) {
+          innerParenStart = this$1.start;
+        }
+        exprList.push(this$1.parseMaybeAssign(false, refDestructuringErrors, this$1.parseParenItem));
+      }
+    }
+    var innerEndPos = this.start, innerEndLoc = this.startLoc;
+    this.expect(types.parenR);
+
+    if (canBeArrow && !this.canInsertSemicolon() && this.eat(types.arrow)) {
+      this.checkPatternErrors(refDestructuringErrors, false);
+      this.checkYieldAwaitInDefaultParams();
+      if (innerParenStart) { this.unexpected(innerParenStart); }
+      this.yieldPos = oldYieldPos;
+      this.awaitPos = oldAwaitPos;
+      return this.parseParenArrowList(startPos, startLoc, exprList)
+    }
+
+    if (!exprList.length || lastIsComma) { this.unexpected(this.lastTokStart); }
+    if (spreadStart) { this.unexpected(spreadStart); }
+    this.checkExpressionErrors(refDestructuringErrors, true);
+    this.yieldPos = oldYieldPos || this.yieldPos;
+    this.awaitPos = oldAwaitPos || this.awaitPos;
+
+    if (exprList.length > 1) {
+      val = this.startNodeAt(innerStartPos, innerStartLoc);
+      val.expressions = exprList;
+      this.finishNodeAt(val, "SequenceExpression", innerEndPos, innerEndLoc);
+    } else {
+      val = exprList[0];
+    }
+  } else {
+    val = this.parseParenExpression();
+  }
+
+  if (this.options.preserveParens) {
+    var par = this.startNodeAt(startPos, startLoc);
+    par.expression = val;
+    return this.finishNode(par, "ParenthesizedExpression")
+  } else {
+    return val
+  }
+};
+
+pp$3.parseParenItem = function(item) {
+  return item
+};
+
+pp$3.parseParenArrowList = function(startPos, startLoc, exprList) {
+  return this.parseArrowExpression(this.startNodeAt(startPos, startLoc), exprList)
+};
+
+// New's precedence is slightly tricky. It must allow its argument to
+// be a `[]` or dot subscript expression, but not a call — at least,
+// not without wrapping it in parentheses. Thus, it uses the noCalls
+// argument to parseSubscripts to prevent it from consuming the
+// argument list.
+
+var empty$1 = [];
+
+pp$3.parseNew = function() {
+  var node = this.startNode();
+  var meta = this.parseIdent(true);
+  if (this.options.ecmaVersion >= 6 && this.eat(types.dot)) {
+    node.meta = meta;
+    node.property = this.parseIdent(true);
+    if (node.property.name !== "target")
+      { this.raiseRecoverable(node.property.start, "The only valid meta property for new is new.target"); }
+    if (!this.inFunction)
+      { this.raiseRecoverable(node.start, "new.target can only be used in functions"); }
+    return this.finishNode(node, "MetaProperty")
+  }
+  var startPos = this.start, startLoc = this.startLoc;
+  node.callee = this.parseSubscripts(this.parseExprAtom(), startPos, startLoc, true);
+  if (this.eat(types.parenL)) { node.arguments = this.parseExprList(types.parenR, this.options.ecmaVersion >= 8, false); }
+  else { node.arguments = empty$1; }
+  return this.finishNode(node, "NewExpression")
+};
+
+// Parse template expression.
+
+pp$3.parseTemplateElement = function(ref) {
+  var isTagged = ref.isTagged;
+
+  var elem = this.startNode();
+  if (this.type === types.invalidTemplate) {
+    if (!isTagged) {
+      this.raiseRecoverable(this.start, "Bad escape sequence in untagged template literal");
+    }
+    elem.value = {
+      raw: this.value,
+      cooked: null
+    };
+  } else {
+    elem.value = {
+      raw: this.input.slice(this.start, this.end).replace(/\r\n?/g, "\n"),
+      cooked: this.value
+    };
+  }
+  this.next();
+  elem.tail = this.type === types.backQuote;
+  return this.finishNode(elem, "TemplateElement")
+};
+
+pp$3.parseTemplate = function(ref) {
+  var this$1 = this;
+  if ( ref === void 0 ) ref = {};
+  var isTagged = ref.isTagged; if ( isTagged === void 0 ) isTagged = false;
+
+  var node = this.startNode();
+  this.next();
+  node.expressions = [];
+  var curElt = this.parseTemplateElement({isTagged: isTagged});
+  node.quasis = [curElt];
+  while (!curElt.tail) {
+    this$1.expect(types.dollarBraceL);
+    node.expressions.push(this$1.parseExpression());
+    this$1.expect(types.braceR);
+    node.quasis.push(curElt = this$1.parseTemplateElement({isTagged: isTagged}));
+  }
+  this.next();
+  return this.finishNode(node, "TemplateLiteral")
+};
+
+pp$3.isAsyncProp = function(prop) {
+  return !prop.computed && prop.key.type === "Identifier" && prop.key.name === "async" &&
+    (this.type === types.name || this.type === types.num || this.type === types.string || this.type === types.bracketL || this.type.keyword) &&
+    !lineBreak.test(this.input.slice(this.lastTokEnd, this.start))
+};
+
+// Parse an object literal or binding pattern.
+
+pp$3.parseObj = function(isPattern, refDestructuringErrors) {
+  var this$1 = this;
+
+  var node = this.startNode(), first = true, propHash = {};
+  node.properties = [];
+  this.next();
+  while (!this.eat(types.braceR)) {
+    if (!first) {
+      this$1.expect(types.comma);
+      if (this$1.afterTrailingComma(types.braceR)) { break }
+    } else { first = false; }
+
+    var prop = this$1.parseProperty(isPattern, refDestructuringErrors);
+    this$1.checkPropClash(prop, propHash);
+    node.properties.push(prop);
+  }
+  return this.finishNode(node, isPattern ? "ObjectPattern" : "ObjectExpression")
+};
+
+pp$3.parseProperty = function(isPattern, refDestructuringErrors) {
+  var prop = this.startNode(), isGenerator, isAsync, startPos, startLoc;
+  if (this.options.ecmaVersion >= 6) {
+    prop.method = false;
+    prop.shorthand = false;
+    if (isPattern || refDestructuringErrors) {
+      startPos = this.start;
+      startLoc = this.startLoc;
+    }
+    if (!isPattern)
+      { isGenerator = this.eat(types.star); }
+  }
+  this.parsePropertyName(prop);
+  if (!isPattern && this.options.ecmaVersion >= 8 && !isGenerator && this.isAsyncProp(prop)) {
+    isAsync = true;
+    this.parsePropertyName(prop, refDestructuringErrors);
+  } else {
+    isAsync = false;
+  }
+  this.parsePropertyValue(prop, isPattern, isGenerator, isAsync, startPos, startLoc, refDestructuringErrors);
+  return this.finishNode(prop, "Property")
+};
+
+pp$3.parsePropertyValue = function(prop, isPattern, isGenerator, isAsync, startPos, startLoc, refDestructuringErrors) {
+  if ((isGenerator || isAsync) && this.type === types.colon)
+    { this.unexpected(); }
+
+  if (this.eat(types.colon)) {
+    prop.value = isPattern ? this.parseMaybeDefault(this.start, this.startLoc) : this.parseMaybeAssign(false, refDestructuringErrors);
+    prop.kind = "init";
+  } else if (this.options.ecmaVersion >= 6 && this.type === types.parenL) {
+    if (isPattern) { this.unexpected(); }
+    prop.kind = "init";
+    prop.method = true;
+    prop.value = this.parseMethod(isGenerator, isAsync);
+  } else if (!isPattern &&
+             this.options.ecmaVersion >= 5 && !prop.computed && prop.key.type === "Identifier" &&
+             (prop.key.name === "get" || prop.key.name === "set") &&
+             (this.type != types.comma && this.type != types.braceR)) {
+    if (isGenerator || isAsync) { this.unexpected(); }
+    prop.kind = prop.key.name;
+    this.parsePropertyName(prop);
+    prop.value = this.parseMethod(false);
+    var paramCount = prop.kind === "get" ? 0 : 1;
+    if (prop.value.params.length !== paramCount) {
+      var start = prop.value.start;
+      if (prop.kind === "get")
+        { this.raiseRecoverable(start, "getter should have no params"); }
+      else
+        { this.raiseRecoverable(start, "setter should have exactly one param"); }
+    } else {
+      if (prop.kind === "set" && prop.value.params[0].type === "RestElement")
+        { this.raiseRecoverable(prop.value.params[0].start, "Setter cannot use rest params"); }
+    }
+  } else if (this.options.ecmaVersion >= 6 && !prop.computed && prop.key.type === "Identifier") {
+    this.checkUnreserved(prop.key);
+    prop.kind = "init";
+    if (isPattern) {
+      prop.value = this.parseMaybeDefault(startPos, startLoc, prop.key);
+    } else if (this.type === types.eq && refDestructuringErrors) {
+      if (refDestructuringErrors.shorthandAssign < 0)
+        { refDestructuringErrors.shorthandAssign = this.start; }
+      prop.value = this.parseMaybeDefault(startPos, startLoc, prop.key);
+    } else {
+      prop.value = prop.key;
+    }
+    prop.shorthand = true;
+  } else { this.unexpected(); }
+};
+
+pp$3.parsePropertyName = function(prop) {
+  if (this.options.ecmaVersion >= 6) {
+    if (this.eat(types.bracketL)) {
+      prop.computed = true;
+      prop.key = this.parseMaybeAssign();
+      this.expect(types.bracketR);
+      return prop.key
+    } else {
+      prop.computed = false;
+    }
+  }
+  return prop.key = this.type === types.num || this.type === types.string ? this.parseExprAtom() : this.parseIdent(true)
+};
+
+// Initialize empty function node.
+
+pp$3.initFunction = function(node) {
+  node.id = null;
+  if (this.options.ecmaVersion >= 6) {
+    node.generator = false;
+    node.expression = false;
+  }
+  if (this.options.ecmaVersion >= 8)
+    { node.async = false; }
+};
+
+// Parse object or class method.
+
+pp$3.parseMethod = function(isGenerator, isAsync) {
+  var node = this.startNode(), oldInGen = this.inGenerator, oldInAsync = this.inAsync,
+      oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos, oldInFunc = this.inFunction;
+
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 6)
+    { node.generator = isGenerator; }
+  if (this.options.ecmaVersion >= 8)
+    { node.async = !!isAsync; }
+
+  this.inGenerator = node.generator;
+  this.inAsync = node.async;
+  this.yieldPos = 0;
+  this.awaitPos = 0;
+  this.inFunction = true;
+  this.enterFunctionScope();
+
+  this.expect(types.parenL);
+  node.params = this.parseBindingList(types.parenR, false, this.options.ecmaVersion >= 8);
+  this.checkYieldAwaitInDefaultParams();
+  this.parseFunctionBody(node, false);
+
+  this.inGenerator = oldInGen;
+  this.inAsync = oldInAsync;
+  this.yieldPos = oldYieldPos;
+  this.awaitPos = oldAwaitPos;
+  this.inFunction = oldInFunc;
+  return this.finishNode(node, "FunctionExpression")
+};
+
+// Parse arrow function expression with given parameters.
+
+pp$3.parseArrowExpression = function(node, params, isAsync) {
+  var oldInGen = this.inGenerator, oldInAsync = this.inAsync,
+      oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos, oldInFunc = this.inFunction;
+
+  this.enterFunctionScope();
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 8)
+    { node.async = !!isAsync; }
+
+  this.inGenerator = false;
+  this.inAsync = node.async;
+  this.yieldPos = 0;
+  this.awaitPos = 0;
+  this.inFunction = true;
+
+  node.params = this.toAssignableList(params, true);
+  this.parseFunctionBody(node, true);
+
+  this.inGenerator = oldInGen;
+  this.inAsync = oldInAsync;
+  this.yieldPos = oldYieldPos;
+  this.awaitPos = oldAwaitPos;
+  this.inFunction = oldInFunc;
+  return this.finishNode(node, "ArrowFunctionExpression")
+};
+
+// Parse function body and check parameters.
+
+pp$3.parseFunctionBody = function(node, isArrowFunction) {
+  var isExpression = isArrowFunction && this.type !== types.braceL;
+  var oldStrict = this.strict, useStrict = false;
+
+  if (isExpression) {
+    node.body = this.parseMaybeAssign();
+    node.expression = true;
+    this.checkParams(node, false);
+  } else {
+    var nonSimple = this.options.ecmaVersion >= 7 && !this.isSimpleParamList(node.params);
+    if (!oldStrict || nonSimple) {
+      useStrict = this.strictDirective(this.end);
+      // If this is a strict mode function, verify that argument names
+      // are not repeated, and it does not try to bind the words `eval`
+      // or `arguments`.
+      if (useStrict && nonSimple)
+        { this.raiseRecoverable(node.start, "Illegal 'use strict' directive in function with non-simple parameter list"); }
+    }
+    // Start a new scope with regard to labels and the `inFunction`
+    // flag (restore them to their old value afterwards).
+    var oldLabels = this.labels;
+    this.labels = [];
+    if (useStrict) { this.strict = true; }
+
+    // Add the params to varDeclaredNames to ensure that an error is thrown
+    // if a let/const declaration in the function clashes with one of the params.
+    this.checkParams(node, !oldStrict && !useStrict && !isArrowFunction && this.isSimpleParamList(node.params));
+    node.body = this.parseBlock(false);
+    node.expression = false;
+    this.adaptDirectivePrologue(node.body.body);
+    this.labels = oldLabels;
+  }
+  this.exitFunctionScope();
+
+  if (this.strict && node.id) {
+    // Ensure the function name isn't a forbidden identifier in strict mode, e.g. 'eval'
+    this.checkLVal(node.id, "none");
+  }
+  this.strict = oldStrict;
+};
+
+pp$3.isSimpleParamList = function(params) {
+  for (var i = 0, list = params; i < list.length; i += 1)
+    {
+    var param = list[i];
+
+    if (param.type !== "Identifier") { return false
+  } }
+  return true
+};
+
+// Checks function params for various disallowed patterns such as using "eval"
+// or "arguments" and duplicate parameters.
+
+pp$3.checkParams = function(node, allowDuplicates) {
+  var this$1 = this;
+
+  var nameHash = {};
+  for (var i = 0, list = node.params; i < list.length; i += 1)
+    {
+    var param = list[i];
+
+    this$1.checkLVal(param, "var", allowDuplicates ? null : nameHash);
+  }
+};
+
+// Parses a comma-separated list of expressions, and returns them as
+// an array. `close` is the token type that ends the list, and
+// `allowEmpty` can be turned on to allow subsequent commas with
+// nothing in between them to be parsed as `null` (which is needed
+// for array literals).
+
+pp$3.parseExprList = function(close, allowTrailingComma, allowEmpty, refDestructuringErrors) {
+  var this$1 = this;
+
+  var elts = [], first = true;
+  while (!this.eat(close)) {
+    if (!first) {
+      this$1.expect(types.comma);
+      if (allowTrailingComma && this$1.afterTrailingComma(close)) { break }
+    } else { first = false; }
+
+    var elt = (void 0);
+    if (allowEmpty && this$1.type === types.comma)
+      { elt = null; }
+    else if (this$1.type === types.ellipsis) {
+      elt = this$1.parseSpread(refDestructuringErrors);
+      if (refDestructuringErrors && this$1.type === types.comma && refDestructuringErrors.trailingComma < 0)
+        { refDestructuringErrors.trailingComma = this$1.start; }
+    } else {
+      elt = this$1.parseMaybeAssign(false, refDestructuringErrors);
+    }
+    elts.push(elt);
+  }
+  return elts
+};
+
+pp$3.checkUnreserved = function(ref) {
+  var start = ref.start;
+  var end = ref.end;
+  var name = ref.name;
+
+  if (this.inGenerator && name === "yield")
+    { this.raiseRecoverable(start, "Can not use 'yield' as identifier inside a generator"); }
+  if (this.inAsync && name === "await")
+    { this.raiseRecoverable(start, "Can not use 'await' as identifier inside an async function"); }
+  if (this.isKeyword(name))
+    { this.raise(start, ("Unexpected keyword '" + name + "'")); }
+  if (this.options.ecmaVersion < 6 &&
+    this.input.slice(start, end).indexOf("\\") != -1) { return }
+  var re = this.strict ? this.reservedWordsStrict : this.reservedWords;
+  if (re.test(name))
+    { this.raiseRecoverable(start, ("The keyword '" + name + "' is reserved")); }
+};
+
+// Parse the next token as an identifier. If `liberal` is true (used
+// when parsing properties), it will also convert keywords into
+// identifiers.
+
+pp$3.parseIdent = function(liberal, isBinding) {
+  var node = this.startNode();
+  if (liberal && this.options.allowReserved == "never") { liberal = false; }
+  if (this.type === types.name) {
+    node.name = this.value;
+  } else if (this.type.keyword) {
+    node.name = this.type.keyword;
+
+    // To fix https://github.com/ternjs/acorn/issues/575
+    // `class` and `function` keywords push new context into this.context.
+    // But there is no chance to pop the context if the keyword is consumed as an identifier such as a property name.
+    // If the previous token is a dot, this does not apply because the context-managing code already ignored the keyword
+    if ((node.name === "class" || node.name === "function") &&
+        (this.lastTokEnd !== this.lastTokStart + 1 || this.input.charCodeAt(this.lastTokStart) !== 46)) {
+      this.context.pop();
+    }
+  } else {
+    this.unexpected();
+  }
+  this.next();
+  this.finishNode(node, "Identifier");
+  if (!liberal) { this.checkUnreserved(node); }
+  return node
+};
+
+// Parses yield expression inside generator.
+
+pp$3.parseYield = function() {
+  if (!this.yieldPos) { this.yieldPos = this.start; }
+
+  var node = this.startNode();
+  this.next();
+  if (this.type == types.semi || this.canInsertSemicolon() || (this.type != types.star && !this.type.startsExpr)) {
+    node.delegate = false;
+    node.argument = null;
+  } else {
+    node.delegate = this.eat(types.star);
+    node.argument = this.parseMaybeAssign();
+  }
+  return this.finishNode(node, "YieldExpression")
+};
+
+pp$3.parseAwait = function() {
+  if (!this.awaitPos) { this.awaitPos = this.start; }
+
+  var node = this.startNode();
+  this.next();
+  node.argument = this.parseMaybeUnary(null, true);
+  return this.finishNode(node, "AwaitExpression")
+};
+
+var pp$4 = Parser.prototype;
+
+// This function is used to raise exceptions on parse errors. It
+// takes an offset integer (into the current `input`) to indicate
+// the location of the error, attaches the position to the end
+// of the error message, and then raises a `SyntaxError` with that
+// message.
+
+pp$4.raise = function(pos, message) {
+  var loc = getLineInfo(this.input, pos);
+  message += " (" + loc.line + ":" + loc.column + ")";
+  var err = new SyntaxError(message);
+  err.pos = pos; err.loc = loc; err.raisedAt = this.pos;
+  throw err
+};
+
+pp$4.raiseRecoverable = pp$4.raise;
+
+pp$4.curPosition = function() {
+  if (this.options.locations) {
+    return new Position(this.curLine, this.pos - this.lineStart)
+  }
+};
+
+var pp$5 = Parser.prototype;
+
+// Object.assign polyfill
+var assign = Object.assign || function(target) {
+  var sources = [], len = arguments.length - 1;
+  while ( len-- > 0 ) sources[ len ] = arguments[ len + 1 ];
+
+  for (var i = 0, list = sources; i < list.length; i += 1) {
+    var source = list[i];
+
+    for (var key in source) {
+      if (has(source, key)) {
+        target[key] = source[key];
+      }
+    }
+  }
+  return target
+};
+
+// The functions in this module keep track of declared variables in the current scope in order to detect duplicate variable names.
+
+pp$5.enterFunctionScope = function() {
+  // var: a hash of var-declared names in the current lexical scope
+  // lexical: a hash of lexically-declared names in the current lexical scope
+  // childVar: a hash of var-declared names in all child lexical scopes of the current lexical scope (within the current function scope)
+  // parentLexical: a hash of lexically-declared names in all parent lexical scopes of the current lexical scope (within the current function scope)
+  this.scopeStack.push({var: {}, lexical: {}, childVar: {}, parentLexical: {}});
+};
+
+pp$5.exitFunctionScope = function() {
+  this.scopeStack.pop();
+};
+
+pp$5.enterLexicalScope = function() {
+  var parentScope = this.scopeStack[this.scopeStack.length - 1];
+  var childScope = {var: {}, lexical: {}, childVar: {}, parentLexical: {}};
+
+  this.scopeStack.push(childScope);
+  assign(childScope.parentLexical, parentScope.lexical, parentScope.parentLexical);
+};
+
+pp$5.exitLexicalScope = function() {
+  var childScope = this.scopeStack.pop();
+  var parentScope = this.scopeStack[this.scopeStack.length - 1];
+
+  assign(parentScope.childVar, childScope.var, childScope.childVar);
+};
+
+/**
+ * A name can be declared with `var` if there are no variables with the same name declared with `let`/`const`
+ * in the current lexical scope or any of the parent lexical scopes in this function.
+ */
+pp$5.canDeclareVarName = function(name) {
+  var currentScope = this.scopeStack[this.scopeStack.length - 1];
+
+  return !has(currentScope.lexical, name) && !has(currentScope.parentLexical, name)
+};
+
+/**
+ * A name can be declared with `let`/`const` if there are no variables with the same name declared with `let`/`const`
+ * in the current scope, and there are no variables with the same name declared with `var` in the current scope or in
+ * any child lexical scopes in this function.
+ */
+pp$5.canDeclareLexicalName = function(name) {
+  var currentScope = this.scopeStack[this.scopeStack.length - 1];
+
+  return !has(currentScope.lexical, name) && !has(currentScope.var, name) && !has(currentScope.childVar, name)
+};
+
+pp$5.declareVarName = function(name) {
+  this.scopeStack[this.scopeStack.length - 1].var[name] = true;
+};
+
+pp$5.declareLexicalName = function(name) {
+  this.scopeStack[this.scopeStack.length - 1].lexical[name] = true;
+};
+
+var Node = function Node(parser, pos, loc) {
+  this.type = "";
+  this.start = pos;
+  this.end = 0;
+  if (parser.options.locations)
+    { this.loc = new SourceLocation(parser, loc); }
+  if (parser.options.directSourceFile)
+    { this.sourceFile = parser.options.directSourceFile; }
+  if (parser.options.ranges)
+    { this.range = [pos, 0]; }
+};
+
+// Start an AST node, attaching a start offset.
+
+var pp$6 = Parser.prototype;
+
+pp$6.startNode = function() {
+  return new Node(this, this.start, this.startLoc)
+};
+
+pp$6.startNodeAt = function(pos, loc) {
+  return new Node(this, pos, loc)
+};
+
+// Finish an AST node, adding `type` and `end` properties.
+
+function finishNodeAt(node, type, pos, loc) {
+  node.type = type;
+  node.end = pos;
+  if (this.options.locations)
+    { node.loc.end = loc; }
+  if (this.options.ranges)
+    { node.range[1] = pos; }
+  return node
+}
+
+pp$6.finishNode = function(node, type) {
+  return finishNodeAt.call(this, node, type, this.lastTokEnd, this.lastTokEndLoc)
+};
+
+// Finish node at given position
+
+pp$6.finishNodeAt = function(node, type, pos, loc) {
+  return finishNodeAt.call(this, node, type, pos, loc)
+};
+
+// The algorithm used to determine whether a regexp can appear at a
+// given point in the program is loosely based on sweet.js' approach.
+// See https://github.com/mozilla/sweet.js/wiki/design
+
+var TokContext = function TokContext(token, isExpr, preserveSpace, override, generator) {
+  this.token = token;
+  this.isExpr = !!isExpr;
+  this.preserveSpace = !!preserveSpace;
+  this.override = override;
+  this.generator = !!generator;
+};
+
+var types$1 = {
+  b_stat: new TokContext("{", false),
+  b_expr: new TokContext("{", true),
+  b_tmpl: new TokContext("${", false),
+  p_stat: new TokContext("(", false),
+  p_expr: new TokContext("(", true),
+  q_tmpl: new TokContext("`", true, true, function (p) { return p.tryReadTemplateToken(); }),
+  f_stat: new TokContext("function", false),
+  f_expr: new TokContext("function", true),
+  f_expr_gen: new TokContext("function", true, false, null, true),
+  f_gen: new TokContext("function", false, false, null, true)
+};
+
+var pp$7 = Parser.prototype;
+
+pp$7.initialContext = function() {
+  return [types$1.b_stat]
+};
+
+pp$7.braceIsBlock = function(prevType) {
+  var parent = this.curContext();
+  if (parent === types$1.f_expr || parent === types$1.f_stat)
+    { return true }
+  if (prevType === types.colon && (parent === types$1.b_stat || parent === types$1.b_expr))
+    { return !parent.isExpr }
+
+  // The check for `tt.name && exprAllowed` detects whether we are
+  // after a `yield` or `of` construct. See the `updateContext` for
+  // `tt.name`.
+  if (prevType === types._return || prevType == types.name && this.exprAllowed)
+    { return lineBreak.test(this.input.slice(this.lastTokEnd, this.start)) }
+  if (prevType === types._else || prevType === types.semi || prevType === types.eof || prevType === types.parenR || prevType == types.arrow)
+    { return true }
+  if (prevType == types.braceL)
+    { return parent === types$1.b_stat }
+  if (prevType == types._var || prevType == types.name)
+    { return false }
+  return !this.exprAllowed
+};
+
+pp$7.inGeneratorContext = function() {
+  var this$1 = this;
+
+  for (var i = this.context.length - 1; i >= 1; i--) {
+    var context = this$1.context[i];
+    if (context.token === "function")
+      { return context.generator }
+  }
+  return false
+};
+
+pp$7.updateContext = function(prevType) {
+  var update, type = this.type;
+  if (type.keyword && prevType == types.dot)
+    { this.exprAllowed = false; }
+  else if (update = type.updateContext)
+    { update.call(this, prevType); }
+  else
+    { this.exprAllowed = type.beforeExpr; }
+};
+
+// Token-specific context update code
+
+types.parenR.updateContext = types.braceR.updateContext = function() {
+  if (this.context.length == 1) {
+    this.exprAllowed = true;
+    return
+  }
+  var out = this.context.pop();
+  if (out === types$1.b_stat && this.curContext().token === "function") {
+    out = this.context.pop();
+  }
+  this.exprAllowed = !out.isExpr;
+};
+
+types.braceL.updateContext = function(prevType) {
+  this.context.push(this.braceIsBlock(prevType) ? types$1.b_stat : types$1.b_expr);
+  this.exprAllowed = true;
+};
+
+types.dollarBraceL.updateContext = function() {
+  this.context.push(types$1.b_tmpl);
+  this.exprAllowed = true;
+};
+
+types.parenL.updateContext = function(prevType) {
+  var statementParens = prevType === types._if || prevType === types._for || prevType === types._with || prevType === types._while;
+  this.context.push(statementParens ? types$1.p_stat : types$1.p_expr);
+  this.exprAllowed = true;
+};
+
+types.incDec.updateContext = function() {
+  // tokExprAllowed stays unchanged
+};
+
+types._function.updateContext = types._class.updateContext = function(prevType) {
+  if (prevType.beforeExpr && prevType !== types.semi && prevType !== types._else &&
+      !((prevType === types.colon || prevType === types.braceL) && this.curContext() === types$1.b_stat))
+    { this.context.push(types$1.f_expr); }
+  else
+    { this.context.push(types$1.f_stat); }
+  this.exprAllowed = false;
+};
+
+types.backQuote.updateContext = function() {
+  if (this.curContext() === types$1.q_tmpl)
+    { this.context.pop(); }
+  else
+    { this.context.push(types$1.q_tmpl); }
+  this.exprAllowed = false;
+};
+
+types.star.updateContext = function(prevType) {
+  if (prevType == types._function) {
+    var index = this.context.length - 1;
+    if (this.context[index] === types$1.f_expr)
+      { this.context[index] = types$1.f_expr_gen; }
+    else
+      { this.context[index] = types$1.f_gen; }
+  }
+  this.exprAllowed = true;
+};
+
+types.name.updateContext = function(prevType) {
+  var allowed = false;
+  if (this.options.ecmaVersion >= 6) {
+    if (this.value == "of" && !this.exprAllowed ||
+        this.value == "yield" && this.inGeneratorContext())
+      { allowed = true; }
+  }
+  this.exprAllowed = allowed;
+};
+
+// Object type used to represent tokens. Note that normally, tokens
+// simply exist as properties on the parser object. This is only
+// used for the onToken callback and the external tokenizer.
+
+var Token = function Token(p) {
+  this.type = p.type;
+  this.value = p.value;
+  this.start = p.start;
+  this.end = p.end;
+  if (p.options.locations)
+    { this.loc = new SourceLocation(p, p.startLoc, p.endLoc); }
+  if (p.options.ranges)
+    { this.range = [p.start, p.end]; }
+};
+
+// ## Tokenizer
+
+var pp$8 = Parser.prototype;
+
+// Are we running under Rhino?
+var isRhino = typeof Packages == "object" && Object.prototype.toString.call(Packages) == "[object JavaPackage]";
+
+// Move to the next token
+
+pp$8.next = function() {
+  if (this.options.onToken)
+    { this.options.onToken(new Token(this)); }
+
+  this.lastTokEnd = this.end;
+  this.lastTokStart = this.start;
+  this.lastTokEndLoc = this.endLoc;
+  this.lastTokStartLoc = this.startLoc;
+  this.nextToken();
+};
+
+pp$8.getToken = function() {
+  this.next();
+  return new Token(this)
+};
+
+// If we're in an ES6 environment, make parsers iterable
+if (typeof Symbol !== "undefined")
+  { pp$8[Symbol.iterator] = function() {
+    var this$1 = this;
+
+    return {
+      next: function () {
+        var token = this$1.getToken();
+        return {
+          done: token.type === types.eof,
+          value: token
+        }
+      }
+    }
+  }; }
+
+// Toggle strict mode. Re-reads the next number or string to please
+// pedantic tests (`"use strict"; 010;` should fail).
+
+pp$8.curContext = function() {
+  return this.context[this.context.length - 1]
+};
+
+// Read a single token, updating the parser object's token-related
+// properties.
+
+pp$8.nextToken = function() {
+  var curContext = this.curContext();
+  if (!curContext || !curContext.preserveSpace) { this.skipSpace(); }
+
+  this.start = this.pos;
+  if (this.options.locations) { this.startLoc = this.curPosition(); }
+  if (this.pos >= this.input.length) { return this.finishToken(types.eof) }
+
+  if (curContext.override) { return curContext.override(this) }
+  else { this.readToken(this.fullCharCodeAtPos()); }
+};
+
+pp$8.readToken = function(code) {
+  // Identifier or keyword. '\uXXXX' sequences are allowed in
+  // identifiers, so '\' also dispatches to that.
+  if (isIdentifierStart(code, this.options.ecmaVersion >= 6) || code === 92 /* '\' */)
+    { return this.readWord() }
+
+  return this.getTokenFromCode(code)
+};
+
+pp$8.fullCharCodeAtPos = function() {
+  var code = this.input.charCodeAt(this.pos);
+  if (code <= 0xd7ff || code >= 0xe000) { return code }
+  var next = this.input.charCodeAt(this.pos + 1);
+  return (code << 10) + next - 0x35fdc00
+};
+
+pp$8.skipBlockComment = function() {
+  var this$1 = this;
+
+  var startLoc = this.options.onComment && this.curPosition();
+  var start = this.pos, end = this.input.indexOf("*/", this.pos += 2);
+  if (end === -1) { this.raise(this.pos - 2, "Unterminated comment"); }
+  this.pos = end + 2;
+  if (this.options.locations) {
+    lineBreakG.lastIndex = start;
+    var match;
+    while ((match = lineBreakG.exec(this.input)) && match.index < this.pos) {
+      ++this$1.curLine;
+      this$1.lineStart = match.index + match[0].length;
+    }
+  }
+  if (this.options.onComment)
+    { this.options.onComment(true, this.input.slice(start + 2, end), start, this.pos,
+                           startLoc, this.curPosition()); }
+};
+
+pp$8.skipLineComment = function(startSkip) {
+  var this$1 = this;
+
+  var start = this.pos;
+  var startLoc = this.options.onComment && this.curPosition();
+  var ch = this.input.charCodeAt(this.pos += startSkip);
+  while (this.pos < this.input.length && !isNewLine(ch)) {
+    ch = this$1.input.charCodeAt(++this$1.pos);
+  }
+  if (this.options.onComment)
+    { this.options.onComment(false, this.input.slice(start + startSkip, this.pos), start, this.pos,
+                           startLoc, this.curPosition()); }
+};
+
+// Called at the start of the parse and after every token. Skips
+// whitespace and comments, and.
+
+pp$8.skipSpace = function() {
+  var this$1 = this;
+
+  loop: while (this.pos < this.input.length) {
+    var ch = this$1.input.charCodeAt(this$1.pos);
+    switch (ch) {
+    case 32: case 160: // ' '
+      ++this$1.pos;
+      break
+    case 13:
+      if (this$1.input.charCodeAt(this$1.pos + 1) === 10) {
+        ++this$1.pos;
+      }
+    case 10: case 8232: case 8233:
+      ++this$1.pos;
+      if (this$1.options.locations) {
+        ++this$1.curLine;
+        this$1.lineStart = this$1.pos;
+      }
+      break
+    case 47: // '/'
+      switch (this$1.input.charCodeAt(this$1.pos + 1)) {
+      case 42: // '*'
+        this$1.skipBlockComment();
+        break
+      case 47:
+        this$1.skipLineComment(2);
+        break
+      default:
+        break loop
+      }
+      break
+    default:
+      if (ch > 8 && ch < 14 || ch >= 5760 && nonASCIIwhitespace.test(String.fromCharCode(ch))) {
+        ++this$1.pos;
+      } else {
+        break loop
+      }
+    }
+  }
+};
+
+// Called at the end of every token. Sets `end`, `val`, and
+// maintains `context` and `exprAllowed`, and skips the space after
+// the token, so that the next one's `start` will point at the
+// right position.
+
+pp$8.finishToken = function(type, val) {
+  this.end = this.pos;
+  if (this.options.locations) { this.endLoc = this.curPosition(); }
+  var prevType = this.type;
+  this.type = type;
+  this.value = val;
+
+  this.updateContext(prevType);
+};
+
+// ### Token reading
+
+// This is the function that is called to fetch the next token. It
+// is somewhat obscure, because it works in character codes rather
+// than characters, and because operator parsing has been inlined
+// into it.
+//
+// All in the name of speed.
+//
+pp$8.readToken_dot = function() {
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next >= 48 && next <= 57) { return this.readNumber(true) }
+  var next2 = this.input.charCodeAt(this.pos + 2);
+  if (this.options.ecmaVersion >= 6 && next === 46 && next2 === 46) { // 46 = dot '.'
+    this.pos += 3;
+    return this.finishToken(types.ellipsis)
+  } else {
+    ++this.pos;
+    return this.finishToken(types.dot)
+  }
+};
+
+pp$8.readToken_slash = function() { // '/'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (this.exprAllowed) { ++this.pos; return this.readRegexp() }
+  if (next === 61) { return this.finishOp(types.assign, 2) }
+  return this.finishOp(types.slash, 1)
+};
+
+pp$8.readToken_mult_modulo_exp = function(code) { // '%*'
+  var next = this.input.charCodeAt(this.pos + 1);
+  var size = 1;
+  var tokentype = code === 42 ? types.star : types.modulo;
+
+  // exponentiation operator ** and **=
+  if (this.options.ecmaVersion >= 7 && code == 42 && next === 42) {
+    ++size;
+    tokentype = types.starstar;
+    next = this.input.charCodeAt(this.pos + 2);
+  }
+
+  if (next === 61) { return this.finishOp(types.assign, size + 1) }
+  return this.finishOp(tokentype, size)
+};
+
+pp$8.readToken_pipe_amp = function(code) { // '|&'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === code) { return this.finishOp(code === 124 ? types.logicalOR : types.logicalAND, 2) }
+  if (next === 61) { return this.finishOp(types.assign, 2) }
+  return this.finishOp(code === 124 ? types.bitwiseOR : types.bitwiseAND, 1)
+};
+
+pp$8.readToken_caret = function() { // '^'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === 61) { return this.finishOp(types.assign, 2) }
+  return this.finishOp(types.bitwiseXOR, 1)
+};
+
+pp$8.readToken_plus_min = function(code) { // '+-'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === code) {
+    if (next == 45 && !this.inModule && this.input.charCodeAt(this.pos + 2) == 62 &&
+        (this.lastTokEnd === 0 || lineBreak.test(this.input.slice(this.lastTokEnd, this.pos)))) {
+      // A `-->` line comment
+      this.skipLineComment(3);
+      this.skipSpace();
+      return this.nextToken()
+    }
+    return this.finishOp(types.incDec, 2)
+  }
+  if (next === 61) { return this.finishOp(types.assign, 2) }
+  return this.finishOp(types.plusMin, 1)
+};
+
+pp$8.readToken_lt_gt = function(code) { // '<>'
+  var next = this.input.charCodeAt(this.pos + 1);
+  var size = 1;
+  if (next === code) {
+    size = code === 62 && this.input.charCodeAt(this.pos + 2) === 62 ? 3 : 2;
+    if (this.input.charCodeAt(this.pos + size) === 61) { return this.finishOp(types.assign, size + 1) }
+    return this.finishOp(types.bitShift, size)
+  }
+  if (next == 33 && code == 60 && !this.inModule && this.input.charCodeAt(this.pos + 2) == 45 &&
+      this.input.charCodeAt(this.pos + 3) == 45) {
+    // `<!--`, an XML-style comment that should be interpreted as a line comment
+    this.skipLineComment(4);
+    this.skipSpace();
+    return this.nextToken()
+  }
+  if (next === 61) { size = 2; }
+  return this.finishOp(types.relational, size)
+};
+
+pp$8.readToken_eq_excl = function(code) { // '=!'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === 61) { return this.finishOp(types.equality, this.input.charCodeAt(this.pos + 2) === 61 ? 3 : 2) }
+  if (code === 61 && next === 62 && this.options.ecmaVersion >= 6) { // '=>'
+    this.pos += 2;
+    return this.finishToken(types.arrow)
+  }
+  return this.finishOp(code === 61 ? types.eq : types.prefix, 1)
+};
+
+pp$8.getTokenFromCode = function(code) {
+  switch (code) {
+    // The interpretation of a dot depends on whether it is followed
+    // by a digit or another two dots.
+  case 46: // '.'
+    return this.readToken_dot()
+
+    // Punctuation tokens.
+  case 40: ++this.pos; return this.finishToken(types.parenL)
+  case 41: ++this.pos; return this.finishToken(types.parenR)
+  case 59: ++this.pos; return this.finishToken(types.semi)
+  case 44: ++this.pos; return this.finishToken(types.comma)
+  case 91: ++this.pos; return this.finishToken(types.bracketL)
+  case 93: ++this.pos; return this.finishToken(types.bracketR)
+  case 123: ++this.pos; return this.finishToken(types.braceL)
+  case 125: ++this.pos; return this.finishToken(types.braceR)
+  case 58: ++this.pos; return this.finishToken(types.colon)
+  case 63: ++this.pos; return this.finishToken(types.question)
+
+  case 96: // '`'
+    if (this.options.ecmaVersion < 6) { break }
+    ++this.pos;
+    return this.finishToken(types.backQuote)
+
+  case 48: // '0'
+    var next = this.input.charCodeAt(this.pos + 1);
+    if (next === 120 || next === 88) { return this.readRadixNumber(16) } // '0x', '0X' - hex number
+    if (this.options.ecmaVersion >= 6) {
+      if (next === 111 || next === 79) { return this.readRadixNumber(8) } // '0o', '0O' - octal number
+      if (next === 98 || next === 66) { return this.readRadixNumber(2) } // '0b', '0B' - binary number
+    }
+    // Anything else beginning with a digit is an integer, octal
+    // number, or float.
+  case 49: case 50: case 51: case 52: case 53: case 54: case 55: case 56: case 57: // 1-9
+    return this.readNumber(false)
+
+    // Quotes produce strings.
+  case 34: case 39: // '"', "'"
+    return this.readString(code)
+
+    // Operators are parsed inline in tiny state machines. '=' (61) is
+    // often referred to. `finishOp` simply skips the amount of
+    // characters it is given as second argument, and returns a token
+    // of the type given by its first argument.
+
+  case 47: // '/'
+    return this.readToken_slash()
+
+  case 37: case 42: // '%*'
+    return this.readToken_mult_modulo_exp(code)
+
+  case 124: case 38: // '|&'
+    return this.readToken_pipe_amp(code)
+
+  case 94: // '^'
+    return this.readToken_caret()
+
+  case 43: case 45: // '+-'
+    return this.readToken_plus_min(code)
+
+  case 60: case 62: // '<>'
+    return this.readToken_lt_gt(code)
+
+  case 61: case 33: // '=!'
+    return this.readToken_eq_excl(code)
+
+  case 126: // '~'
+    return this.finishOp(types.prefix, 1)
+  }
+
+  this.raise(this.pos, "Unexpected character '" + codePointToString(code) + "'");
+};
+
+pp$8.finishOp = function(type, size) {
+  var str = this.input.slice(this.pos, this.pos + size);
+  this.pos += size;
+  return this.finishToken(type, str)
+};
+
+// Parse a regular expression. Some context-awareness is necessary,
+// since a '/' inside a '[]' set does not end the expression.
+
+function tryCreateRegexp(src, flags, throwErrorAt, parser) {
+  try {
+    return new RegExp(src, flags)
+  } catch (e) {
+    if (throwErrorAt !== undefined) {
+      if (e instanceof SyntaxError) { parser.raise(throwErrorAt, "Error parsing regular expression: " + e.message); }
+      throw e
+    }
+  }
+}
+
+var regexpUnicodeSupport = !!tryCreateRegexp("\uffff", "u");
+
+pp$8.readRegexp = function() {
+  var this$1 = this;
+
+  var escaped, inClass, start = this.pos;
+  for (;;) {
+    if (this$1.pos >= this$1.input.length) { this$1.raise(start, "Unterminated regular expression"); }
+    var ch = this$1.input.charAt(this$1.pos);
+    if (lineBreak.test(ch)) { this$1.raise(start, "Unterminated regular expression"); }
+    if (!escaped) {
+      if (ch === "[") { inClass = true; }
+      else if (ch === "]" && inClass) { inClass = false; }
+      else if (ch === "/" && !inClass) { break }
+      escaped = ch === "\\";
+    } else { escaped = false; }
+    ++this$1.pos;
+  }
+  var content = this.input.slice(start, this.pos);
+  ++this.pos;
+  // Need to use `readWord1` because '\uXXXX' sequences are allowed
+  // here (don't ask).
+  var mods = this.readWord1();
+  var tmp = content, tmpFlags = "";
+  if (mods) {
+    var validFlags = /^[gim]*$/;
+    if (this.options.ecmaVersion >= 6) { validFlags = /^[gimuy]*$/; }
+    if (!validFlags.test(mods)) { this.raise(start, "Invalid regular expression flag"); }
+    if (mods.indexOf("u") >= 0) {
+      if (regexpUnicodeSupport) {
+        tmpFlags = "u";
+      } else {
+        // Replace each astral symbol and every Unicode escape sequence that
+        // possibly represents an astral symbol or a paired surrogate with a
+        // single ASCII symbol to avoid throwing on regular expressions that
+        // are only valid in combination with the `/u` flag.
+        // Note: replacing with the ASCII symbol `x` might cause false
+        // negatives in unlikely scenarios. For example, `[\u{61}-b]` is a
+        // perfectly valid pattern that is equivalent to `[a-b]`, but it would
+        // be replaced by `[x-b]` which throws an error.
+        tmp = tmp.replace(/\\u\{([0-9a-fA-F]+)\}/g, function (_match, code, offset) {
+          code = Number("0x" + code);
+          if (code > 0x10FFFF) { this$1.raise(start + offset + 3, "Code point out of bounds"); }
+          return "x"
+        });
+        tmp = tmp.replace(/\\u([a-fA-F0-9]{4})|[\uD800-\uDBFF][\uDC00-\uDFFF]/g, "x");
+        tmpFlags = tmpFlags.replace("u", "");
+      }
+    }
+  }
+  // Detect invalid regular expressions.
+  var value = null;
+  // Rhino's regular expression parser is flaky and throws uncatchable exceptions,
+  // so don't do detection if we are running under Rhino
+  if (!isRhino) {
+    tryCreateRegexp(tmp, tmpFlags, start, this);
+    // Get a regular expression object for this pattern-flag pair, or `null` in
+    // case the current environment doesn't support the flags it uses.
+    value = tryCreateRegexp(content, mods);
+  }
+  return this.finishToken(types.regexp, {pattern: content, flags: mods, value: value})
+};
+
+// Read an integer in the given radix. Return null if zero digits
+// were read, the integer value otherwise. When `len` is given, this
+// will return `null` unless the integer has exactly `len` digits.
+
+pp$8.readInt = function(radix, len) {
+  var this$1 = this;
+
+  var start = this.pos, total = 0;
+  for (var i = 0, e = len == null ? Infinity : len; i < e; ++i) {
+    var code = this$1.input.charCodeAt(this$1.pos), val = (void 0);
+    if (code >= 97) { val = code - 97 + 10; } // a
+    else if (code >= 65) { val = code - 65 + 10; } // A
+    else if (code >= 48 && code <= 57) { val = code - 48; } // 0-9
+    else { val = Infinity; }
+    if (val >= radix) { break }
+    ++this$1.pos;
+    total = total * radix + val;
+  }
+  if (this.pos === start || len != null && this.pos - start !== len) { return null }
+
+  return total
+};
+
+pp$8.readRadixNumber = function(radix) {
+  this.pos += 2; // 0x
+  var val = this.readInt(radix);
+  if (val == null) { this.raise(this.start + 2, "Expected number in radix " + radix); }
+  if (isIdentifierStart(this.fullCharCodeAtPos())) { this.raise(this.pos, "Identifier directly after number"); }
+  return this.finishToken(types.num, val)
+};
+
+// Read an integer, octal integer, or floating-point number.
+
+pp$8.readNumber = function(startsWithDot) {
+  var start = this.pos, isFloat = false, octal = this.input.charCodeAt(this.pos) === 48;
+  if (!startsWithDot && this.readInt(10) === null) { this.raise(start, "Invalid number"); }
+  if (octal && this.pos == start + 1) { octal = false; }
+  var next = this.input.charCodeAt(this.pos);
+  if (next === 46 && !octal) { // '.'
+    ++this.pos;
+    this.readInt(10);
+    isFloat = true;
+    next = this.input.charCodeAt(this.pos);
+  }
+  if ((next === 69 || next === 101) && !octal) { // 'eE'
+    next = this.input.charCodeAt(++this.pos);
+    if (next === 43 || next === 45) { ++this.pos; } // '+-'
+    if (this.readInt(10) === null) { this.raise(start, "Invalid number"); }
+    isFloat = true;
+  }
+  if (isIdentifierStart(this.fullCharCodeAtPos())) { this.raise(this.pos, "Identifier directly after number"); }
+
+  var str = this.input.slice(start, this.pos), val;
+  if (isFloat) { val = parseFloat(str); }
+  else if (!octal || str.length === 1) { val = parseInt(str, 10); }
+  else if (this.strict) { this.raise(start, "Invalid number"); }
+  else if (/[89]/.test(str)) { val = parseInt(str, 10); }
+  else { val = parseInt(str, 8); }
+  return this.finishToken(types.num, val)
+};
+
+// Read a string value, interpreting backslash-escapes.
+
+pp$8.readCodePoint = function() {
+  var ch = this.input.charCodeAt(this.pos), code;
+
+  if (ch === 123) { // '{'
+    if (this.options.ecmaVersion < 6) { this.unexpected(); }
+    var codePos = ++this.pos;
+    code = this.readHexChar(this.input.indexOf("}", this.pos) - this.pos);
+    ++this.pos;
+    if (code > 0x10FFFF) { this.invalidStringToken(codePos, "Code point out of bounds"); }
+  } else {
+    code = this.readHexChar(4);
+  }
+  return code
+};
+
+function codePointToString(code) {
+  // UTF-16 Decoding
+  if (code <= 0xFFFF) { return String.fromCharCode(code) }
+  code -= 0x10000;
+  return String.fromCharCode((code >> 10) + 0xD800, (code & 1023) + 0xDC00)
+}
+
+pp$8.readString = function(quote) {
+  var this$1 = this;
+
+  var out = "", chunkStart = ++this.pos;
+  for (;;) {
+    if (this$1.pos >= this$1.input.length) { this$1.raise(this$1.start, "Unterminated string constant"); }
+    var ch = this$1.input.charCodeAt(this$1.pos);
+    if (ch === quote) { break }
+    if (ch === 92) { // '\'
+      out += this$1.input.slice(chunkStart, this$1.pos);
+      out += this$1.readEscapedChar(false);
+      chunkStart = this$1.pos;
+    } else {
+      if (isNewLine(ch)) { this$1.raise(this$1.start, "Unterminated string constant"); }
+      ++this$1.pos;
+    }
+  }
+  out += this.input.slice(chunkStart, this.pos++);
+  return this.finishToken(types.string, out)
+};
+
+// Reads template string tokens.
+
+var INVALID_TEMPLATE_ESCAPE_ERROR = {};
+
+pp$8.tryReadTemplateToken = function() {
+  this.inTemplateElement = true;
+  try {
+    this.readTmplToken();
+  } catch (err) {
+    if (err === INVALID_TEMPLATE_ESCAPE_ERROR) {
+      this.readInvalidTemplateToken();
+    } else {
+      throw err
+    }
+  }
+
+  this.inTemplateElement = false;
+};
+
+pp$8.invalidStringToken = function(position, message) {
+  if (this.inTemplateElement && this.options.ecmaVersion >= 9) {
+    throw INVALID_TEMPLATE_ESCAPE_ERROR
+  } else {
+    this.raise(position, message);
+  }
+};
+
+pp$8.readTmplToken = function() {
+  var this$1 = this;
+
+  var out = "", chunkStart = this.pos;
+  for (;;) {
+    if (this$1.pos >= this$1.input.length) { this$1.raise(this$1.start, "Unterminated template"); }
+    var ch = this$1.input.charCodeAt(this$1.pos);
+    if (ch === 96 || ch === 36 && this$1.input.charCodeAt(this$1.pos + 1) === 123) { // '`', '${'
+      if (this$1.pos === this$1.start && (this$1.type === types.template || this$1.type === types.invalidTemplate)) {
+        if (ch === 36) {
+          this$1.pos += 2;
+          return this$1.finishToken(types.dollarBraceL)
+        } else {
+          ++this$1.pos;
+          return this$1.finishToken(types.backQuote)
+        }
+      }
+      out += this$1.input.slice(chunkStart, this$1.pos);
+      return this$1.finishToken(types.template, out)
+    }
+    if (ch === 92) { // '\'
+      out += this$1.input.slice(chunkStart, this$1.pos);
+      out += this$1.readEscapedChar(true);
+      chunkStart = this$1.pos;
+    } else if (isNewLine(ch)) {
+      out += this$1.input.slice(chunkStart, this$1.pos);
+      ++this$1.pos;
+      switch (ch) {
+      case 13:
+        if (this$1.input.charCodeAt(this$1.pos) === 10) { ++this$1.pos; }
+      case 10:
+        out += "\n";
+        break
+      default:
+        out += String.fromCharCode(ch);
+        break
+      }
+      if (this$1.options.locations) {
+        ++this$1.curLine;
+        this$1.lineStart = this$1.pos;
+      }
+      chunkStart = this$1.pos;
+    } else {
+      ++this$1.pos;
+    }
+  }
+};
+
+// Reads a template token to search for the end, without validating any escape sequences
+pp$8.readInvalidTemplateToken = function() {
+  var this$1 = this;
+
+  for (; this.pos < this.input.length; this.pos++) {
+    switch (this$1.input[this$1.pos]) {
+    case "\\":
+      ++this$1.pos;
+      break
+
+    case "$":
+      if (this$1.input[this$1.pos + 1] !== "{") {
+        break
+      }
+    // falls through
+
+    case "`":
+      return this$1.finishToken(types.invalidTemplate, this$1.input.slice(this$1.start, this$1.pos))
+
+    // no default
+    }
+  }
+  this.raise(this.start, "Unterminated template");
+};
+
+// Used to read escaped characters
+
+pp$8.readEscapedChar = function(inTemplate) {
+  var ch = this.input.charCodeAt(++this.pos);
+  ++this.pos;
+  switch (ch) {
+  case 110: return "\n" // 'n' -> '\n'
+  case 114: return "\r" // 'r' -> '\r'
+  case 120: return String.fromCharCode(this.readHexChar(2)) // 'x'
+  case 117: return codePointToString(this.readCodePoint()) // 'u'
+  case 116: return "\t" // 't' -> '\t'
+  case 98: return "\b" // 'b' -> '\b'
+  case 118: return "\u000b" // 'v' -> '\u000b'
+  case 102: return "\f" // 'f' -> '\f'
+  case 13: if (this.input.charCodeAt(this.pos) === 10) { ++this.pos; } // '\r\n'
+  case 10: // ' \n'
+    if (this.options.locations) { this.lineStart = this.pos; ++this.curLine; }
+    return ""
+  default:
+    if (ch >= 48 && ch <= 55) {
+      var octalStr = this.input.substr(this.pos - 1, 3).match(/^[0-7]+/)[0];
+      var octal = parseInt(octalStr, 8);
+      if (octal > 255) {
+        octalStr = octalStr.slice(0, -1);
+        octal = parseInt(octalStr, 8);
+      }
+      if (octalStr !== "0" && (this.strict || inTemplate)) {
+        this.invalidStringToken(this.pos - 2, "Octal literal in strict mode");
+      }
+      this.pos += octalStr.length - 1;
+      return String.fromCharCode(octal)
+    }
+    return String.fromCharCode(ch)
+  }
+};
+
+// Used to read character escape sequences ('\x', '\u', '\U').
+
+pp$8.readHexChar = function(len) {
+  var codePos = this.pos;
+  var n = this.readInt(16, len);
+  if (n === null) { this.invalidStringToken(codePos, "Bad character escape sequence"); }
+  return n
+};
+
+// Read an identifier, and return it as a string. Sets `this.containsEsc`
+// to whether the word contained a '\u' escape.
+//
+// Incrementally adds only escaped chars, adding other chunks as-is
+// as a micro-optimization.
+
+pp$8.readWord1 = function() {
+  var this$1 = this;
+
+  this.containsEsc = false;
+  var word = "", first = true, chunkStart = this.pos;
+  var astral = this.options.ecmaVersion >= 6;
+  while (this.pos < this.input.length) {
+    var ch = this$1.fullCharCodeAtPos();
+    if (isIdentifierChar(ch, astral)) {
+      this$1.pos += ch <= 0xffff ? 1 : 2;
+    } else if (ch === 92) { // "\"
+      this$1.containsEsc = true;
+      word += this$1.input.slice(chunkStart, this$1.pos);
+      var escStart = this$1.pos;
+      if (this$1.input.charCodeAt(++this$1.pos) != 117) // "u"
+        { this$1.invalidStringToken(this$1.pos, "Expecting Unicode escape sequence \\uXXXX"); }
+      ++this$1.pos;
+      var esc = this$1.readCodePoint();
+      if (!(first ? isIdentifierStart : isIdentifierChar)(esc, astral))
+        { this$1.invalidStringToken(escStart, "Invalid Unicode escape"); }
+      word += codePointToString(esc);
+      chunkStart = this$1.pos;
+    } else {
+      break
+    }
+    first = false;
+  }
+  return word + this.input.slice(chunkStart, this.pos)
+};
+
+// Read an identifier or keyword token. Will check for reserved
+// words when necessary.
+
+pp$8.readWord = function() {
+  var word = this.readWord1();
+  var type = types.name;
+  if (this.keywords.test(word)) {
+    if (this.containsEsc) { this.raiseRecoverable(this.start, "Escape sequence in keyword " + word); }
+    type = keywords$1[word];
+  }
+  return this.finishToken(type, word)
+};
+
+// Acorn is a tiny, fast JavaScript parser written in JavaScript.
+//
+// Acorn was written by Marijn Haverbeke, Ingvar Stepanyan, and
+// various contributors and released under an MIT license.
+//
+// Git repositories for Acorn are available at
+//
+//     http://marijnhaverbeke.nl/git/acorn
+//     https://github.com/ternjs/acorn.git
+//
+// Please use the [github bug tracker][ghbt] to report issues.
+//
+// [ghbt]: https://github.com/ternjs/acorn/issues
+//
+// This file defines the main parser interface. The library also comes
+// with a [error-tolerant parser][dammit] and an
+// [abstract syntax tree walker][walk], defined in other files.
+//
+// [dammit]: acorn_loose.js
+// [walk]: util/walk.js
+
+var version = "5.2.1";
+
+// The main exported interface (under `self.acorn` when in the
+// browser) is a `parse` function that takes a code string and
+// returns an abstract syntax tree as specified by [Mozilla parser
+// API][api].
+//
+// [api]: https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API
+
+function parse(input, options) {
+  return new Parser(options, input).parse()
+}
+
+// This function tries to parse a single expression at a given
+// offset in a string. Useful for parsing mixed-language formats
+// that embed JavaScript expressions.
+
+function parseExpressionAt(input, pos, options) {
+  var p = new Parser(options, input, pos);
+  p.nextToken();
+  return p.parseExpression()
+}
+
+// Acorn is organized as a tokenizer and a recursive-descent parser.
+// The `tokenizer` export provides an interface to the tokenizer.
+
+function tokenizer(input, options) {
+  return new Parser(options, input)
+}
+
+// This is a terrible kludge to support the existing, pre-ES6
+// interface where the loose parser module retroactively adds exports
+// to this module.
+var parse_dammit;
+var LooseParser;
+var pluginsLoose; // eslint-disable-line camelcase
+function addLooseExports(parse, Parser$$1, plugins$$1) {
+  parse_dammit = parse; // eslint-disable-line camelcase
+  LooseParser = Parser$$1;
+  pluginsLoose = plugins$$1;
+}
+
+export { version, parse, parseExpressionAt, tokenizer, parse_dammit, LooseParser, pluginsLoose, addLooseExports, Parser, plugins, defaultOptions, Position, SourceLocation, getLineInfo, Node, TokenType, types as tokTypes, keywords$1 as keywordTypes, TokContext, types$1 as tokContexts, isIdentifierChar, isIdentifierStart, Token, isNewLine, lineBreak, lineBreakG, nonASCIIwhitespace };
diff --git a/deps/acorn/dist/acorn.js b/deps/acorn/dist/acorn.js
new file mode 100644
index 0000000000..4f0dd5d212
--- /dev/null
+++ b/deps/acorn/dist/acorn.js
@@ -0,0 +1,3765 @@
+(function (global, factory) {
+	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
+	typeof define === 'function' && define.amd ? define(['exports'], factory) :
+	(factory((global.acorn = global.acorn || {})));
+}(this, (function (exports) { 'use strict';
+
+// Reserved word lists for various dialects of the language
+
+var reservedWords = {
+  3: "abstract boolean byte char class double enum export extends final float goto implements import int interface long native package private protected public short static super synchronized throws transient volatile",
+  5: "class enum extends super const export import",
+  6: "enum",
+  strict: "implements interface let package private protected public static yield",
+  strictBind: "eval arguments"
+};
+
+// And the keywords
+
+var ecma5AndLessKeywords = "break case catch continue debugger default do else finally for function if return switch throw try var while with null true false instanceof typeof void delete new in this";
+
+var keywords = {
+  5: ecma5AndLessKeywords,
+  6: ecma5AndLessKeywords + " const class extends export import super"
+};
+
+// ## Character categories
+
+// Big ugly regular expressions that match characters in the
+// whitespace, identifier, and identifier-start categories. These
+// are only applied when a character is found to actually have a
+// code point above 128.
+// Generated by `bin/generate-identifier-regex.js`.
+
+var nonASCIIidentifierStartChars = "\xaa\xb5\xba\xc0-\xd6\xd8-\xf6\xf8-\u02c1\u02c6-\u02d1\u02e0-\u02e4\u02ec\u02ee\u0370-\u0374\u0376\u0377\u037a-\u037d\u037f\u0386\u0388-\u038a\u038c\u038e-\u03a1\u03a3-\u03f5\u03f7-\u0481\u048a-\u052f\u0531-\u0556\u0559\u0561-\u0587\u05d0-\u05ea\u05f0-\u05f2\u0620-\u064a\u066e\u066f\u0671-\u06d3\u06d5\u06e5\u06e6\u06ee\u06ef\u06fa-\u06fc\u06ff\u0710\u0712-\u072f\u074d-\u07a5\u07b1\u07ca-\u07ea\u07f4\u07f5\u07fa\u0800-\u0815\u081a\u0824\u0828\u0840-\u0858\u08a0-\u08b4\u08b6-\u08bd\u0904-\u0939\u093d\u0950\u0958-\u0961\u0971-\u0980\u0985-\u098c\u098f\u0990\u0993-\u09a8\u09aa-\u09b0\u09b2\u09b6-\u09b9\u09bd\u09ce\u09dc\u09dd\u09df-\u09e1\u09f0\u09f1\u0a05-\u0a0a\u0a0f\u0a10\u0a13-\u0a28\u0a2a-\u0a30\u0a32\u0a33\u0a35\u0a36\u0a38\u0a39\u0a59-\u0a5c\u0a5e\u0a72-\u0a74\u0a85-\u0a8d\u0a8f-\u0a91\u0a93-\u0aa8\u0aaa-\u0ab0\u0ab2\u0ab3\u0ab5-\u0ab9\u0abd\u0ad0\u0ae0\u0ae1\u0af9\u0b05-\u0b0c\u0b0f\u0b10\u0b13-\u0b28\u0b2a-\u0b30\u0b32\u0b33\u0b35-\u0b39\u0b3d\u0b5c\u0b5d\u0b5f-\u0b61\u0b71\u0b83\u0b85-\u0b8a\u0b8e-\u0b90\u0b92-\u0b95\u0b99\u0b9a\u0b9c\u0b9e\u0b9f\u0ba3\u0ba4\u0ba8-\u0baa\u0bae-\u0bb9\u0bd0\u0c05-\u0c0c\u0c0e-\u0c10\u0c12-\u0c28\u0c2a-\u0c39\u0c3d\u0c58-\u0c5a\u0c60\u0c61\u0c80\u0c85-\u0c8c\u0c8e-\u0c90\u0c92-\u0ca8\u0caa-\u0cb3\u0cb5-\u0cb9\u0cbd\u0cde\u0ce0\u0ce1\u0cf1\u0cf2\u0d05-\u0d0c\u0d0e-\u0d10\u0d12-\u0d3a\u0d3d\u0d4e\u0d54-\u0d56\u0d5f-\u0d61\u0d7a-\u0d7f\u0d85-\u0d96\u0d9a-\u0db1\u0db3-\u0dbb\u0dbd\u0dc0-\u0dc6\u0e01-\u0e30\u0e32\u0e33\u0e40-\u0e46\u0e81\u0e82\u0e84\u0e87\u0e88\u0e8a\u0e8d\u0e94-\u0e97\u0e99-\u0e9f\u0ea1-\u0ea3\u0ea5\u0ea7\u0eaa\u0eab\u0ead-\u0eb0\u0eb2\u0eb3\u0ebd\u0ec0-\u0ec4\u0ec6\u0edc-\u0edf\u0f00\u0f40-\u0f47\u0f49-\u0f6c\u0f88-\u0f8c\u1000-\u102a\u103f\u1050-\u1055\u105a-\u105d\u1061\u1065\u1066\u106e-\u1070\u1075-\u1081\u108e\u10a0-\u10c5\u10c7\u10cd\u10d0-\u10fa\u10fc-\u1248\u124a-\u124d\u1250-\u1256\u1258\u125a-\u125d\u1260-\u1288\u128a-\u128d\u1290-\u12b0\u12b2-\u12b5\u12b8-\u12be\u12c0\u12c2-\u12c5\u12c8-\u12d6\u12d8-\u1310\u1312-\u1315\u1318-\u135a\u1380-\u138f\u13a0-\u13f5\u13f8-\u13fd\u1401-\u166c\u166f-\u167f\u1681-\u169a\u16a0-\u16ea\u16ee-\u16f8\u1700-\u170c\u170e-\u1711\u1720-\u1731\u1740-\u1751\u1760-\u176c\u176e-\u1770\u1780-\u17b3\u17d7\u17dc\u1820-\u1877\u1880-\u18a8\u18aa\u18b0-\u18f5\u1900-\u191e\u1950-\u196d\u1970-\u1974\u1980-\u19ab\u19b0-\u19c9\u1a00-\u1a16\u1a20-\u1a54\u1aa7\u1b05-\u1b33\u1b45-\u1b4b\u1b83-\u1ba0\u1bae\u1baf\u1bba-\u1be5\u1c00-\u1c23\u1c4d-\u1c4f\u1c5a-\u1c7d\u1c80-\u1c88\u1ce9-\u1cec\u1cee-\u1cf1\u1cf5\u1cf6\u1d00-\u1dbf\u1e00-\u1f15\u1f18-\u1f1d\u1f20-\u1f45\u1f48-\u1f4d\u1f50-\u1f57\u1f59\u1f5b\u1f5d\u1f5f-\u1f7d\u1f80-\u1fb4\u1fb6-\u1fbc\u1fbe\u1fc2-\u1fc4\u1fc6-\u1fcc\u1fd0-\u1fd3\u1fd6-\u1fdb\u1fe0-\u1fec\u1ff2-\u1ff4\u1ff6-\u1ffc\u2071\u207f\u2090-\u209c\u2102\u2107\u210a-\u2113\u2115\u2118-\u211d\u2124\u2126\u2128\u212a-\u2139\u213c-\u213f\u2145-\u2149\u214e\u2160-\u2188\u2c00-\u2c2e\u2c30-\u2c5e\u2c60-\u2ce4\u2ceb-\u2cee\u2cf2\u2cf3\u2d00-\u2d25\u2d27\u2d2d\u2d30-\u2d67\u2d6f\u2d80-\u2d96\u2da0-\u2da6\u2da8-\u2dae\u2db0-\u2db6\u2db8-\u2dbe\u2dc0-\u2dc6\u2dc8-\u2dce\u2dd0-\u2dd6\u2dd8-\u2dde\u3005-\u3007\u3021-\u3029\u3031-\u3035\u3038-\u303c\u3041-\u3096\u309b-\u309f\u30a1-\u30fa\u30fc-\u30ff\u3105-\u312d\u3131-\u318e\u31a0-\u31ba\u31f0-\u31ff\u3400-\u4db5\u4e00-\u9fd5\ua000-\ua48c\ua4d0-\ua4fd\ua500-\ua60c\ua610-\ua61f\ua62a\ua62b\ua640-\ua66e\ua67f-\ua69d\ua6a0-\ua6ef\ua717-\ua71f\ua722-\ua788\ua78b-\ua7ae\ua7b0-\ua7b7\ua7f7-\ua801\ua803-\ua805\ua807-\ua80a\ua80c-\ua822\ua840-\ua873\ua882-\ua8b3\ua8f2-\ua8f7\ua8fb\ua8fd\ua90a-\ua925\ua930-\ua946\ua960-\ua97c\ua984-\ua9b2\ua9cf\ua9e0-\ua9e4\ua9e6-\ua9ef\ua9fa-\ua9fe\uaa00-\uaa28\uaa40-\uaa42\uaa44-\uaa4b\uaa60-\uaa76\uaa7a\uaa7e-\uaaaf\uaab1\uaab5\uaab6\uaab9-\uaabd\uaac0\uaac2\uaadb-\uaadd\uaae0-\uaaea\uaaf2-\uaaf4\uab01-\uab06\uab09-\uab0e\uab11-\uab16\uab20-\uab26\uab28-\uab2e\uab30-\uab5a\uab5c-\uab65\uab70-\uabe2\uac00-\ud7a3\ud7b0-\ud7c6\ud7cb-\ud7fb\uf900-\ufa6d\ufa70-\ufad9\ufb00-\ufb06\ufb13-\ufb17\ufb1d\ufb1f-\ufb28\ufb2a-\ufb36\ufb38-\ufb3c\ufb3e\ufb40\ufb41\ufb43\ufb44\ufb46-\ufbb1\ufbd3-\ufd3d\ufd50-\ufd8f\ufd92-\ufdc7\ufdf0-\ufdfb\ufe70-\ufe74\ufe76-\ufefc\uff21-\uff3a\uff41-\uff5a\uff66-\uffbe\uffc2-\uffc7\uffca-\uffcf\uffd2-\uffd7\uffda-\uffdc";
+var nonASCIIidentifierChars = "\u200c\u200d\xb7\u0300-\u036f\u0387\u0483-\u0487\u0591-\u05bd\u05bf\u05c1\u05c2\u05c4\u05c5\u05c7\u0610-\u061a\u064b-\u0669\u0670\u06d6-\u06dc\u06df-\u06e4\u06e7\u06e8\u06ea-\u06ed\u06f0-\u06f9\u0711\u0730-\u074a\u07a6-\u07b0\u07c0-\u07c9\u07eb-\u07f3\u0816-\u0819\u081b-\u0823\u0825-\u0827\u0829-\u082d\u0859-\u085b\u08d4-\u08e1\u08e3-\u0903\u093a-\u093c\u093e-\u094f\u0951-\u0957\u0962\u0963\u0966-\u096f\u0981-\u0983\u09bc\u09be-\u09c4\u09c7\u09c8\u09cb-\u09cd\u09d7\u09e2\u09e3\u09e6-\u09ef\u0a01-\u0a03\u0a3c\u0a3e-\u0a42\u0a47\u0a48\u0a4b-\u0a4d\u0a51\u0a66-\u0a71\u0a75\u0a81-\u0a83\u0abc\u0abe-\u0ac5\u0ac7-\u0ac9\u0acb-\u0acd\u0ae2\u0ae3\u0ae6-\u0aef\u0b01-\u0b03\u0b3c\u0b3e-\u0b44\u0b47\u0b48\u0b4b-\u0b4d\u0b56\u0b57\u0b62\u0b63\u0b66-\u0b6f\u0b82\u0bbe-\u0bc2\u0bc6-\u0bc8\u0bca-\u0bcd\u0bd7\u0be6-\u0bef\u0c00-\u0c03\u0c3e-\u0c44\u0c46-\u0c48\u0c4a-\u0c4d\u0c55\u0c56\u0c62\u0c63\u0c66-\u0c6f\u0c81-\u0c83\u0cbc\u0cbe-\u0cc4\u0cc6-\u0cc8\u0cca-\u0ccd\u0cd5\u0cd6\u0ce2\u0ce3\u0ce6-\u0cef\u0d01-\u0d03\u0d3e-\u0d44\u0d46-\u0d48\u0d4a-\u0d4d\u0d57\u0d62\u0d63\u0d66-\u0d6f\u0d82\u0d83\u0dca\u0dcf-\u0dd4\u0dd6\u0dd8-\u0ddf\u0de6-\u0def\u0df2\u0df3\u0e31\u0e34-\u0e3a\u0e47-\u0e4e\u0e50-\u0e59\u0eb1\u0eb4-\u0eb9\u0ebb\u0ebc\u0ec8-\u0ecd\u0ed0-\u0ed9\u0f18\u0f19\u0f20-\u0f29\u0f35\u0f37\u0f39\u0f3e\u0f3f\u0f71-\u0f84\u0f86\u0f87\u0f8d-\u0f97\u0f99-\u0fbc\u0fc6\u102b-\u103e\u1040-\u1049\u1056-\u1059\u105e-\u1060\u1062-\u1064\u1067-\u106d\u1071-\u1074\u1082-\u108d\u108f-\u109d\u135d-\u135f\u1369-\u1371\u1712-\u1714\u1732-\u1734\u1752\u1753\u1772\u1773\u17b4-\u17d3\u17dd\u17e0-\u17e9\u180b-\u180d\u1810-\u1819\u18a9\u1920-\u192b\u1930-\u193b\u1946-\u194f\u19d0-\u19da\u1a17-\u1a1b\u1a55-\u1a5e\u1a60-\u1a7c\u1a7f-\u1a89\u1a90-\u1a99\u1ab0-\u1abd\u1b00-\u1b04\u1b34-\u1b44\u1b50-\u1b59\u1b6b-\u1b73\u1b80-\u1b82\u1ba1-\u1bad\u1bb0-\u1bb9\u1be6-\u1bf3\u1c24-\u1c37\u1c40-\u1c49\u1c50-\u1c59\u1cd0-\u1cd2\u1cd4-\u1ce8\u1ced\u1cf2-\u1cf4\u1cf8\u1cf9\u1dc0-\u1df5\u1dfb-\u1dff\u203f\u2040\u2054\u20d0-\u20dc\u20e1\u20e5-\u20f0\u2cef-\u2cf1\u2d7f\u2de0-\u2dff\u302a-\u302f\u3099\u309a\ua620-\ua629\ua66f\ua674-\ua67d\ua69e\ua69f\ua6f0\ua6f1\ua802\ua806\ua80b\ua823-\ua827\ua880\ua881\ua8b4-\ua8c5\ua8d0-\ua8d9\ua8e0-\ua8f1\ua900-\ua909\ua926-\ua92d\ua947-\ua953\ua980-\ua983\ua9b3-\ua9c0\ua9d0-\ua9d9\ua9e5\ua9f0-\ua9f9\uaa29-\uaa36\uaa43\uaa4c\uaa4d\uaa50-\uaa59\uaa7b-\uaa7d\uaab0\uaab2-\uaab4\uaab7\uaab8\uaabe\uaabf\uaac1\uaaeb-\uaaef\uaaf5\uaaf6\uabe3-\uabea\uabec\uabed\uabf0-\uabf9\ufb1e\ufe00-\ufe0f\ufe20-\ufe2f\ufe33\ufe34\ufe4d-\ufe4f\uff10-\uff19\uff3f";
+
+var nonASCIIidentifierStart = new RegExp("[" + nonASCIIidentifierStartChars + "]");
+var nonASCIIidentifier = new RegExp("[" + nonASCIIidentifierStartChars + nonASCIIidentifierChars + "]");
+
+nonASCIIidentifierStartChars = nonASCIIidentifierChars = null;
+
+// These are a run-length and offset encoded representation of the
+// >0xffff code points that are a valid part of identifiers. The
+// offset starts at 0x10000, and each pair of numbers represents an
+// offset to the next range, and then a size of the range. They were
+// generated by bin/generate-identifier-regex.js
+
+// eslint-disable-next-line comma-spacing
+var astralIdentifierStartCodes = [0,11,2,25,2,18,2,1,2,14,3,13,35,122,70,52,268,28,4,48,48,31,17,26,6,37,11,29,3,35,5,7,2,4,43,157,19,35,5,35,5,39,9,51,157,310,10,21,11,7,153,5,3,0,2,43,2,1,4,0,3,22,11,22,10,30,66,18,2,1,11,21,11,25,71,55,7,1,65,0,16,3,2,2,2,26,45,28,4,28,36,7,2,27,28,53,11,21,11,18,14,17,111,72,56,50,14,50,785,52,76,44,33,24,27,35,42,34,4,0,13,47,15,3,22,0,2,0,36,17,2,24,85,6,2,0,2,3,2,14,2,9,8,46,39,7,3,1,3,21,2,6,2,1,2,4,4,0,19,0,13,4,159,52,19,3,54,47,21,1,2,0,185,46,42,3,37,47,21,0,60,42,86,25,391,63,32,0,449,56,264,8,2,36,18,0,50,29,881,921,103,110,18,195,2749,1070,4050,582,8634,568,8,30,114,29,19,47,17,3,32,20,6,18,881,68,12,0,67,12,65,0,32,6124,20,754,9486,1,3071,106,6,12,4,8,8,9,5991,84,2,70,2,1,3,0,3,1,3,3,2,11,2,0,2,6,2,64,2,3,3,7,2,6,2,27,2,3,2,4,2,0,4,6,2,339,3,24,2,24,2,30,2,24,2,30,2,24,2,30,2,24,2,30,2,24,2,7,4149,196,60,67,1213,3,2,26,2,1,2,0,3,0,2,9,2,3,2,0,2,0,7,0,5,0,2,0,2,0,2,2,2,1,2,0,3,0,2,0,2,0,2,0,2,0,2,1,2,0,3,3,2,6,2,3,2,3,2,0,2,9,2,16,6,2,2,4,2,16,4421,42710,42,4148,12,221,3,5761,10591,541];
+
+// eslint-disable-next-line comma-spacing
+var astralIdentifierCodes = [509,0,227,0,150,4,294,9,1368,2,2,1,6,3,41,2,5,0,166,1,1306,2,54,14,32,9,16,3,46,10,54,9,7,2,37,13,2,9,52,0,13,2,49,13,10,2,4,9,83,11,7,0,161,11,6,9,7,3,57,0,2,6,3,1,3,2,10,0,11,1,3,6,4,4,193,17,10,9,87,19,13,9,214,6,3,8,28,1,83,16,16,9,82,12,9,9,84,14,5,9,423,9,838,7,2,7,17,9,57,21,2,13,19882,9,135,4,60,6,26,9,1016,45,17,3,19723,1,5319,4,4,5,9,7,3,6,31,3,149,2,1418,49,513,54,5,49,9,0,15,0,23,4,2,14,1361,6,2,16,3,6,2,1,2,4,2214,6,110,6,6,9,792487,239];
+
+// This has a complexity linear to the value of the code. The
+// assumption is that looking up astral identifier characters is
+// rare.
+function isInAstralSet(code, set) {
+  var pos = 0x10000;
+  for (var i = 0; i < set.length; i += 2) {
+    pos += set[i];
+    if (pos > code) { return false }
+    pos += set[i + 1];
+    if (pos >= code) { return true }
+  }
+}
+
+// Test whether a given character code starts an identifier.
+
+function isIdentifierStart(code, astral) {
+  if (code < 65) { return code === 36 }
+  if (code < 91) { return true }
+  if (code < 97) { return code === 95 }
+  if (code < 123) { return true }
+  if (code <= 0xffff) { return code >= 0xaa && nonASCIIidentifierStart.test(String.fromCharCode(code)) }
+  if (astral === false) { return false }
+  return isInAstralSet(code, astralIdentifierStartCodes)
+}
+
+// Test whether a given character is part of an identifier.
+
+function isIdentifierChar(code, astral) {
+  if (code < 48) { return code === 36 }
+  if (code < 58) { return true }
+  if (code < 65) { return false }
+  if (code < 91) { return true }
+  if (code < 97) { return code === 95 }
+  if (code < 123) { return true }
+  if (code <= 0xffff) { return code >= 0xaa && nonASCIIidentifier.test(String.fromCharCode(code)) }
+  if (astral === false) { return false }
+  return isInAstralSet(code, astralIdentifierStartCodes) || isInAstralSet(code, astralIdentifierCodes)
+}
+
+// ## Token types
+
+// The assignment of fine-grained, information-carrying type objects
+// allows the tokenizer to store the information it has about a
+// token in a way that is very cheap for the parser to look up.
+
+// All token type variables start with an underscore, to make them
+// easy to recognize.
+
+// The `beforeExpr` property is used to disambiguate between regular
+// expressions and divisions. It is set on all token types that can
+// be followed by an expression (thus, a slash after them would be a
+// regular expression).
+//
+// The `startsExpr` property is used to check if the token ends a
+// `yield` expression. It is set on all token types that either can
+// directly start an expression (like a quotation mark) or can
+// continue an expression (like the body of a string).
+//
+// `isLoop` marks a keyword as starting a loop, which is important
+// to know when parsing a label, in order to allow or disallow
+// continue jumps to that label.
+
+var TokenType = function TokenType(label, conf) {
+  if ( conf === void 0 ) conf = {};
+
+  this.label = label;
+  this.keyword = conf.keyword;
+  this.beforeExpr = !!conf.beforeExpr;
+  this.startsExpr = !!conf.startsExpr;
+  this.isLoop = !!conf.isLoop;
+  this.isAssign = !!conf.isAssign;
+  this.prefix = !!conf.prefix;
+  this.postfix = !!conf.postfix;
+  this.binop = conf.binop || null;
+  this.updateContext = null;
+};
+
+function binop(name, prec) {
+  return new TokenType(name, {beforeExpr: true, binop: prec})
+}
+var beforeExpr = {beforeExpr: true};
+var startsExpr = {startsExpr: true};
+
+// Map keyword names to token types.
+
+var keywords$1 = {};
+
+// Succinct definitions of keyword token types
+function kw(name, options) {
+  if ( options === void 0 ) options = {};
+
+  options.keyword = name;
+  return keywords$1[name] = new TokenType(name, options)
+}
+
+var types = {
+  num: new TokenType("num", startsExpr),
+  regexp: new TokenType("regexp", startsExpr),
+  string: new TokenType("string", startsExpr),
+  name: new TokenType("name", startsExpr),
+  eof: new TokenType("eof"),
+
+  // Punctuation token types.
+  bracketL: new TokenType("[", {beforeExpr: true, startsExpr: true}),
+  bracketR: new TokenType("]"),
+  braceL: new TokenType("{", {beforeExpr: true, startsExpr: true}),
+  braceR: new TokenType("}"),
+  parenL: new TokenType("(", {beforeExpr: true, startsExpr: true}),
+  parenR: new TokenType(")"),
+  comma: new TokenType(",", beforeExpr),
+  semi: new TokenType(";", beforeExpr),
+  colon: new TokenType(":", beforeExpr),
+  dot: new TokenType("."),
+  question: new TokenType("?", beforeExpr),
+  arrow: new TokenType("=>", beforeExpr),
+  template: new TokenType("template"),
+  invalidTemplate: new TokenType("invalidTemplate"),
+  ellipsis: new TokenType("...", beforeExpr),
+  backQuote: new TokenType("`", startsExpr),
+  dollarBraceL: new TokenType("${", {beforeExpr: true, startsExpr: true}),
+
+  // Operators. These carry several kinds of properties to help the
+  // parser use them properly (the presence of these properties is
+  // what categorizes them as operators).
+  //
+  // `binop`, when present, specifies that this operator is a binary
+  // operator, and will refer to its precedence.
+  //
+  // `prefix` and `postfix` mark the operator as a prefix or postfix
+  // unary operator.
+  //
+  // `isAssign` marks all of `=`, `+=`, `-=` etcetera, which act as
+  // binary operators with a very low precedence, that should result
+  // in AssignmentExpression nodes.
+
+  eq: new TokenType("=", {beforeExpr: true, isAssign: true}),
+  assign: new TokenType("_=", {beforeExpr: true, isAssign: true}),
+  incDec: new TokenType("++/--", {prefix: true, postfix: true, startsExpr: true}),
+  prefix: new TokenType("!/~", {beforeExpr: true, prefix: true, startsExpr: true}),
+  logicalOR: binop("||", 1),
+  logicalAND: binop("&&", 2),
+  bitwiseOR: binop("|", 3),
+  bitwiseXOR: binop("^", 4),
+  bitwiseAND: binop("&", 5),
+  equality: binop("==/!=/===/!==", 6),
+  relational: binop("</>/<=/>=", 7),
+  bitShift: binop("<</>>/>>>", 8),
+  plusMin: new TokenType("+/-", {beforeExpr: true, binop: 9, prefix: true, startsExpr: true}),
+  modulo: binop("%", 10),
+  star: binop("*", 10),
+  slash: binop("/", 10),
+  starstar: new TokenType("**", {beforeExpr: true}),
+
+  // Keyword token types.
+  _break: kw("break"),
+  _case: kw("case", beforeExpr),
+  _catch: kw("catch"),
+  _continue: kw("continue"),
+  _debugger: kw("debugger"),
+  _default: kw("default", beforeExpr),
+  _do: kw("do", {isLoop: true, beforeExpr: true}),
+  _else: kw("else", beforeExpr),
+  _finally: kw("finally"),
+  _for: kw("for", {isLoop: true}),
+  _function: kw("function", startsExpr),
+  _if: kw("if"),
+  _return: kw("return", beforeExpr),
+  _switch: kw("switch"),
+  _throw: kw("throw", beforeExpr),
+  _try: kw("try"),
+  _var: kw("var"),
+  _const: kw("const"),
+  _while: kw("while", {isLoop: true}),
+  _with: kw("with"),
+  _new: kw("new", {beforeExpr: true, startsExpr: true}),
+  _this: kw("this", startsExpr),
+  _super: kw("super", startsExpr),
+  _class: kw("class", startsExpr),
+  _extends: kw("extends", beforeExpr),
+  _export: kw("export"),
+  _import: kw("import"),
+  _null: kw("null", startsExpr),
+  _true: kw("true", startsExpr),
+  _false: kw("false", startsExpr),
+  _in: kw("in", {beforeExpr: true, binop: 7}),
+  _instanceof: kw("instanceof", {beforeExpr: true, binop: 7}),
+  _typeof: kw("typeof", {beforeExpr: true, prefix: true, startsExpr: true}),
+  _void: kw("void", {beforeExpr: true, prefix: true, startsExpr: true}),
+  _delete: kw("delete", {beforeExpr: true, prefix: true, startsExpr: true})
+};
+
+// Matches a whole line break (where CRLF is considered a single
+// line break). Used to count lines.
+
+var lineBreak = /\r\n?|\n|\u2028|\u2029/;
+var lineBreakG = new RegExp(lineBreak.source, "g");
+
+function isNewLine(code) {
+  return code === 10 || code === 13 || code === 0x2028 || code === 0x2029
+}
+
+var nonASCIIwhitespace = /[\u1680\u180e\u2000-\u200a\u202f\u205f\u3000\ufeff]/;
+
+var skipWhiteSpace = /(?:\s|\/\/.*|\/\*[^]*?\*\/)*/g;
+
+var ref = Object.prototype;
+var hasOwnProperty = ref.hasOwnProperty;
+var toString = ref.toString;
+
+// Checks if an object has a property.
+
+function has(obj, propName) {
+  return hasOwnProperty.call(obj, propName)
+}
+
+var isArray = Array.isArray || (function (obj) { return (
+  toString.call(obj) === "[object Array]"
+); });
+
+// These are used when `options.locations` is on, for the
+// `startLoc` and `endLoc` properties.
+
+var Position = function Position(line, col) {
+  this.line = line;
+  this.column = col;
+};
+
+Position.prototype.offset = function offset (n) {
+  return new Position(this.line, this.column + n)
+};
+
+var SourceLocation = function SourceLocation(p, start, end) {
+  this.start = start;
+  this.end = end;
+  if (p.sourceFile !== null) { this.source = p.sourceFile; }
+};
+
+// The `getLineInfo` function is mostly useful when the
+// `locations` option is off (for performance reasons) and you
+// want to find the line/column position for a given character
+// offset. `input` should be the code string that the offset refers
+// into.
+
+function getLineInfo(input, offset) {
+  for (var line = 1, cur = 0;;) {
+    lineBreakG.lastIndex = cur;
+    var match = lineBreakG.exec(input);
+    if (match && match.index < offset) {
+      ++line;
+      cur = match.index + match[0].length;
+    } else {
+      return new Position(line, offset - cur)
+    }
+  }
+}
+
+// A second optional argument can be given to further configure
+// the parser process. These options are recognized:
+
+var defaultOptions = {
+  // `ecmaVersion` indicates the ECMAScript version to parse. Must
+  // be either 3, 5, 6 (2015), 7 (2016), or 8 (2017). This influences support
+  // for strict mode, the set of reserved words, and support for
+  // new syntax features. The default is 7.
+  ecmaVersion: 7,
+  // `sourceType` indicates the mode the code should be parsed in.
+  // Can be either `"script"` or `"module"`. This influences global
+  // strict mode and parsing of `import` and `export` declarations.
+  sourceType: "script",
+  // `onInsertedSemicolon` can be a callback that will be called
+  // when a semicolon is automatically inserted. It will be passed
+  // th position of the comma as an offset, and if `locations` is
+  // enabled, it is given the location as a `{line, column}` object
+  // as second argument.
+  onInsertedSemicolon: null,
+  // `onTrailingComma` is similar to `onInsertedSemicolon`, but for
+  // trailing commas.
+  onTrailingComma: null,
+  // By default, reserved words are only enforced if ecmaVersion >= 5.
+  // Set `allowReserved` to a boolean value to explicitly turn this on
+  // an off. When this option has the value "never", reserved words
+  // and keywords can also not be used as property names.
+  allowReserved: null,
+  // When enabled, a return at the top level is not considered an
+  // error.
+  allowReturnOutsideFunction: false,
+  // When enabled, import/export statements are not constrained to
+  // appearing at the top of the program.
+  allowImportExportEverywhere: false,
+  // When enabled, hashbang directive in the beginning of file
+  // is allowed and treated as a line comment.
+  allowHashBang: false,
+  // When `locations` is on, `loc` properties holding objects with
+  // `start` and `end` properties in `{line, column}` form (with
+  // line being 1-based and column 0-based) will be attached to the
+  // nodes.
+  locations: false,
+  // A function can be passed as `onToken` option, which will
+  // cause Acorn to call that function with object in the same
+  // format as tokens returned from `tokenizer().getToken()`. Note
+  // that you are not allowed to call the parser from the
+  // callback—that will corrupt its internal state.
+  onToken: null,
+  // A function can be passed as `onComment` option, which will
+  // cause Acorn to call that function with `(block, text, start,
+  // end)` parameters whenever a comment is skipped. `block` is a
+  // boolean indicating whether this is a block (`/* */`) comment,
+  // `text` is the content of the comment, and `start` and `end` are
+  // character offsets that denote the start and end of the comment.
+  // When the `locations` option is on, two more parameters are
+  // passed, the full `{line, column}` locations of the start and
+  // end of the comments. Note that you are not allowed to call the
+  // parser from the callback—that will corrupt its internal state.
+  onComment: null,
+  // Nodes have their start and end characters offsets recorded in
+  // `start` and `end` properties (directly on the node, rather than
+  // the `loc` object, which holds line/column data. To also add a
+  // [semi-standardized][range] `range` property holding a `[start,
+  // end]` array with the same numbers, set the `ranges` option to
+  // `true`.
+  //
+  // [range]: https://bugzilla.mozilla.org/show_bug.cgi?id=745678
+  ranges: false,
+  // It is possible to parse multiple files into a single AST by
+  // passing the tree produced by parsing the first file as
+  // `program` option in subsequent parses. This will add the
+  // toplevel forms of the parsed file to the `Program` (top) node
+  // of an existing parse tree.
+  program: null,
+  // When `locations` is on, you can pass this to record the source
+  // file in every node's `loc` object.
+  sourceFile: null,
+  // This value, if given, is stored in every node, whether
+  // `locations` is on or off.
+  directSourceFile: null,
+  // When enabled, parenthesized expressions are represented by
+  // (non-standard) ParenthesizedExpression nodes
+  preserveParens: false,
+  plugins: {}
+};
+
+// Interpret and default an options object
+
+function getOptions(opts) {
+  var options = {};
+
+  for (var opt in defaultOptions)
+    { options[opt] = opts && has(opts, opt) ? opts[opt] : defaultOptions[opt]; }
+
+  if (options.ecmaVersion >= 2015)
+    { options.ecmaVersion -= 2009; }
+
+  if (options.allowReserved == null)
+    { options.allowReserved = options.ecmaVersion < 5; }
+
+  if (isArray(options.onToken)) {
+    var tokens = options.onToken;
+    options.onToken = function (token) { return tokens.push(token); };
+  }
+  if (isArray(options.onComment))
+    { options.onComment = pushComment(options, options.onComment); }
+
+  return options
+}
+
+function pushComment(options, array) {
+  return function(block, text, start, end, startLoc, endLoc) {
+    var comment = {
+      type: block ? "Block" : "Line",
+      value: text,
+      start: start,
+      end: end
+    };
+    if (options.locations)
+      { comment.loc = new SourceLocation(this, startLoc, endLoc); }
+    if (options.ranges)
+      { comment.range = [start, end]; }
+    array.push(comment);
+  }
+}
+
+// Registered plugins
+var plugins = {};
+
+function keywordRegexp(words) {
+  return new RegExp("^(?:" + words.replace(/ /g, "|") + ")$")
+}
+
+var Parser = function Parser(options, input, startPos) {
+  this.options = options = getOptions(options);
+  this.sourceFile = options.sourceFile;
+  this.keywords = keywordRegexp(keywords[options.ecmaVersion >= 6 ? 6 : 5]);
+  var reserved = "";
+  if (!options.allowReserved) {
+    for (var v = options.ecmaVersion;; v--)
+      { if (reserved = reservedWords[v]) { break } }
+    if (options.sourceType == "module") { reserved += " await"; }
+  }
+  this.reservedWords = keywordRegexp(reserved);
+  var reservedStrict = (reserved ? reserved + " " : "") + reservedWords.strict;
+  this.reservedWordsStrict = keywordRegexp(reservedStrict);
+  this.reservedWordsStrictBind = keywordRegexp(reservedStrict + " " + reservedWords.strictBind);
+  this.input = String(input);
+
+  // Used to signal to callers of `readWord1` whether the word
+  // contained any escape sequences. This is needed because words with
+  // escape sequences must not be interpreted as keywords.
+  this.containsEsc = false;
+
+  // Load plugins
+  this.loadPlugins(options.plugins);
+
+  // Set up token state
+
+  // The current position of the tokenizer in the input.
+  if (startPos) {
+    this.pos = startPos;
+    this.lineStart = this.input.lastIndexOf("\n", startPos - 1) + 1;
+    this.curLine = this.input.slice(0, this.lineStart).split(lineBreak).length;
+  } else {
+    this.pos = this.lineStart = 0;
+    this.curLine = 1;
+  }
+
+  // Properties of the current token:
+  // Its type
+  this.type = types.eof;
+  // For tokens that include more information than their type, the value
+  this.value = null;
+  // Its start and end offset
+  this.start = this.end = this.pos;
+  // And, if locations are used, the {line, column} object
+  // corresponding to those offsets
+  this.startLoc = this.endLoc = this.curPosition();
+
+  // Position information for the previous token
+  this.lastTokEndLoc = this.lastTokStartLoc = null;
+  this.lastTokStart = this.lastTokEnd = this.pos;
+
+  // The context stack is used to superficially track syntactic
+  // context to predict whether a regular expression is allowed in a
+  // given position.
+  this.context = this.initialContext();
+  this.exprAllowed = true;
+
+  // Figure out if it's a module code.
+  this.inModule = options.sourceType === "module";
+  this.strict = this.inModule || this.strictDirective(this.pos);
+
+  // Used to signify the start of a potential arrow function
+  this.potentialArrowAt = -1;
+
+  // Flags to track whether we are in a function, a generator, an async function.
+  this.inFunction = this.inGenerator = this.inAsync = false;
+  // Positions to delayed-check that yield/await does not exist in default parameters.
+  this.yieldPos = this.awaitPos = 0;
+  // Labels in scope.
+  this.labels = [];
+
+  // If enabled, skip leading hashbang line.
+  if (this.pos === 0 && options.allowHashBang && this.input.slice(0, 2) === "#!")
+    { this.skipLineComment(2); }
+
+  // Scope tracking for duplicate variable names (see scope.js)
+  this.scopeStack = [];
+  this.enterFunctionScope();
+};
+
+// DEPRECATED Kept for backwards compatibility until 3.0 in case a plugin uses them
+Parser.prototype.isKeyword = function isKeyword (word) { return this.keywords.test(word) };
+Parser.prototype.isReservedWord = function isReservedWord (word) { return this.reservedWords.test(word) };
+
+Parser.prototype.extend = function extend (name, f) {
+  this[name] = f(this[name]);
+};
+
+Parser.prototype.loadPlugins = function loadPlugins (pluginConfigs) {
+    var this$1 = this;
+
+  for (var name in pluginConfigs) {
+    var plugin = plugins[name];
+    if (!plugin) { throw new Error("Plugin '" + name + "' not found") }
+    plugin(this$1, pluginConfigs[name]);
+  }
+};
+
+Parser.prototype.parse = function parse () {
+  var node = this.options.program || this.startNode();
+  this.nextToken();
+  return this.parseTopLevel(node)
+};
+
+var pp = Parser.prototype;
+
+// ## Parser utilities
+
+var literal = /^(?:'((?:\\.|[^'])*?)'|"((?:\\.|[^"])*?)"|;)/;
+pp.strictDirective = function(start) {
+  var this$1 = this;
+
+  for (;;) {
+    skipWhiteSpace.lastIndex = start;
+    start += skipWhiteSpace.exec(this$1.input)[0].length;
+    var match = literal.exec(this$1.input.slice(start));
+    if (!match) { return false }
+    if ((match[1] || match[2]) == "use strict") { return true }
+    start += match[0].length;
+  }
+};
+
+// Predicate that tests whether the next token is of the given
+// type, and if yes, consumes it as a side effect.
+
+pp.eat = function(type) {
+  if (this.type === type) {
+    this.next();
+    return true
+  } else {
+    return false
+  }
+};
+
+// Tests whether parsed token is a contextual keyword.
+
+pp.isContextual = function(name) {
+  return this.type === types.name && this.value === name
+};
+
+// Consumes contextual keyword if possible.
+
+pp.eatContextual = function(name) {
+  return this.value === name && this.eat(types.name)
+};
+
+// Asserts that following token is given contextual keyword.
+
+pp.expectContextual = function(name) {
+  if (!this.eatContextual(name)) { this.unexpected(); }
+};
+
+// Test whether a semicolon can be inserted at the current position.
+
+pp.canInsertSemicolon = function() {
+  return this.type === types.eof ||
+    this.type === types.braceR ||
+    lineBreak.test(this.input.slice(this.lastTokEnd, this.start))
+};
+
+pp.insertSemicolon = function() {
+  if (this.canInsertSemicolon()) {
+    if (this.options.onInsertedSemicolon)
+      { this.options.onInsertedSemicolon(this.lastTokEnd, this.lastTokEndLoc); }
+    return true
+  }
+};
+
+// Consume a semicolon, or, failing that, see if we are allowed to
+// pretend that there is a semicolon at this position.
+
+pp.semicolon = function() {
+  if (!this.eat(types.semi) && !this.insertSemicolon()) { this.unexpected(); }
+};
+
+pp.afterTrailingComma = function(tokType, notNext) {
+  if (this.type == tokType) {
+    if (this.options.onTrailingComma)
+      { this.options.onTrailingComma(this.lastTokStart, this.lastTokStartLoc); }
+    if (!notNext)
+      { this.next(); }
+    return true
+  }
+};
+
+// Expect a token of a given type. If found, consume it, otherwise,
+// raise an unexpected token error.
+
+pp.expect = function(type) {
+  this.eat(type) || this.unexpected();
+};
+
+// Raise an unexpected token error.
+
+pp.unexpected = function(pos) {
+  this.raise(pos != null ? pos : this.start, "Unexpected token");
+};
+
+function DestructuringErrors() {
+  this.shorthandAssign =
+  this.trailingComma =
+  this.parenthesizedAssign =
+  this.parenthesizedBind =
+    -1;
+}
+
+pp.checkPatternErrors = function(refDestructuringErrors, isAssign) {
+  if (!refDestructuringErrors) { return }
+  if (refDestructuringErrors.trailingComma > -1)
+    { this.raiseRecoverable(refDestructuringErrors.trailingComma, "Comma is not permitted after the rest element"); }
+  var parens = isAssign ? refDestructuringErrors.parenthesizedAssign : refDestructuringErrors.parenthesizedBind;
+  if (parens > -1) { this.raiseRecoverable(parens, "Parenthesized pattern"); }
+};
+
+pp.checkExpressionErrors = function(refDestructuringErrors, andThrow) {
+  var pos = refDestructuringErrors ? refDestructuringErrors.shorthandAssign : -1;
+  if (!andThrow) { return pos >= 0 }
+  if (pos > -1) { this.raise(pos, "Shorthand property assignments are valid only in destructuring patterns"); }
+};
+
+pp.checkYieldAwaitInDefaultParams = function() {
+  if (this.yieldPos && (!this.awaitPos || this.yieldPos < this.awaitPos))
+    { this.raise(this.yieldPos, "Yield expression cannot be a default value"); }
+  if (this.awaitPos)
+    { this.raise(this.awaitPos, "Await expression cannot be a default value"); }
+};
+
+pp.isSimpleAssignTarget = function(expr) {
+  if (expr.type === "ParenthesizedExpression")
+    { return this.isSimpleAssignTarget(expr.expression) }
+  return expr.type === "Identifier" || expr.type === "MemberExpression"
+};
+
+var pp$1 = Parser.prototype;
+
+// ### Statement parsing
+
+// Parse a program. Initializes the parser, reads any number of
+// statements, and wraps them in a Program node.  Optionally takes a
+// `program` argument.  If present, the statements will be appended
+// to its body instead of creating a new node.
+
+pp$1.parseTopLevel = function(node) {
+  var this$1 = this;
+
+  var exports = {};
+  if (!node.body) { node.body = []; }
+  while (this.type !== types.eof) {
+    var stmt = this$1.parseStatement(true, true, exports);
+    node.body.push(stmt);
+  }
+  this.adaptDirectivePrologue(node.body);
+  this.next();
+  if (this.options.ecmaVersion >= 6) {
+    node.sourceType = this.options.sourceType;
+  }
+  return this.finishNode(node, "Program")
+};
+
+var loopLabel = {kind: "loop"};
+var switchLabel = {kind: "switch"};
+
+pp$1.isLet = function() {
+  if (this.type !== types.name || this.options.ecmaVersion < 6 || this.value != "let") { return false }
+  skipWhiteSpace.lastIndex = this.pos;
+  var skip = skipWhiteSpace.exec(this.input);
+  var next = this.pos + skip[0].length, nextCh = this.input.charCodeAt(next);
+  if (nextCh === 91 || nextCh == 123) { return true } // '{' and '['
+  if (isIdentifierStart(nextCh, true)) {
+    var pos = next + 1;
+    while (isIdentifierChar(this.input.charCodeAt(pos), true)) { ++pos; }
+    var ident = this.input.slice(next, pos);
+    if (!this.isKeyword(ident)) { return true }
+  }
+  return false
+};
+
+// check 'async [no LineTerminator here] function'
+// - 'async /*foo*/ function' is OK.
+// - 'async /*\n*/ function' is invalid.
+pp$1.isAsyncFunction = function() {
+  if (this.type !== types.name || this.options.ecmaVersion < 8 || this.value != "async")
+    { return false }
+
+  skipWhiteSpace.lastIndex = this.pos;
+  var skip = skipWhiteSpace.exec(this.input);
+  var next = this.pos + skip[0].length;
+  return !lineBreak.test(this.input.slice(this.pos, next)) &&
+    this.input.slice(next, next + 8) === "function" &&
+    (next + 8 == this.input.length || !isIdentifierChar(this.input.charAt(next + 8)))
+};
+
+// Parse a single statement.
+//
+// If expecting a statement and finding a slash operator, parse a
+// regular expression literal. This is to handle cases like
+// `if (foo) /blah/.exec(foo)`, where looking at the previous token
+// does not help.
+
+pp$1.parseStatement = function(declaration, topLevel, exports) {
+  var starttype = this.type, node = this.startNode(), kind;
+
+  if (this.isLet()) {
+    starttype = types._var;
+    kind = "let";
+  }
+
+  // Most types of statements are recognized by the keyword they
+  // start with. Many are trivial to parse, some require a bit of
+  // complexity.
+
+  switch (starttype) {
+  case types._break: case types._continue: return this.parseBreakContinueStatement(node, starttype.keyword)
+  case types._debugger: return this.parseDebuggerStatement(node)
+  case types._do: return this.parseDoStatement(node)
+  case types._for: return this.parseForStatement(node)
+  case types._function:
+    if (!declaration && this.options.ecmaVersion >= 6) { this.unexpected(); }
+    return this.parseFunctionStatement(node, false)
+  case types._class:
+    if (!declaration) { this.unexpected(); }
+    return this.parseClass(node, true)
+  case types._if: return this.parseIfStatement(node)
+  case types._return: return this.parseReturnStatement(node)
+  case types._switch: return this.parseSwitchStatement(node)
+  case types._throw: return this.parseThrowStatement(node)
+  case types._try: return this.parseTryStatement(node)
+  case types._const: case types._var:
+    kind = kind || this.value;
+    if (!declaration && kind != "var") { this.unexpected(); }
+    return this.parseVarStatement(node, kind)
+  case types._while: return this.parseWhileStatement(node)
+  case types._with: return this.parseWithStatement(node)
+  case types.braceL: return this.parseBlock()
+  case types.semi: return this.parseEmptyStatement(node)
+  case types._export:
+  case types._import:
+    if (!this.options.allowImportExportEverywhere) {
+      if (!topLevel)
+        { this.raise(this.start, "'import' and 'export' may only appear at the top level"); }
+      if (!this.inModule)
+        { this.raise(this.start, "'import' and 'export' may appear only with 'sourceType: module'"); }
+    }
+    return starttype === types._import ? this.parseImport(node) : this.parseExport(node, exports)
+
+    // If the statement does not start with a statement keyword or a
+    // brace, it's an ExpressionStatement or LabeledStatement. We
+    // simply start parsing an expression, and afterwards, if the
+    // next token is a colon and the expression was a simple
+    // Identifier node, we switch to interpreting it as a label.
+  default:
+    if (this.isAsyncFunction() && declaration) {
+      this.next();
+      return this.parseFunctionStatement(node, true)
+    }
+
+    var maybeName = this.value, expr = this.parseExpression();
+    if (starttype === types.name && expr.type === "Identifier" && this.eat(types.colon))
+      { return this.parseLabeledStatement(node, maybeName, expr) }
+    else { return this.parseExpressionStatement(node, expr) }
+  }
+};
+
+pp$1.parseBreakContinueStatement = function(node, keyword) {
+  var this$1 = this;
+
+  var isBreak = keyword == "break";
+  this.next();
+  if (this.eat(types.semi) || this.insertSemicolon()) { node.label = null; }
+  else if (this.type !== types.name) { this.unexpected(); }
+  else {
+    node.label = this.parseIdent();
+    this.semicolon();
+  }
+
+  // Verify that there is an actual destination to break or
+  // continue to.
+  var i = 0;
+  for (; i < this.labels.length; ++i) {
+    var lab = this$1.labels[i];
+    if (node.label == null || lab.name === node.label.name) {
+      if (lab.kind != null && (isBreak || lab.kind === "loop")) { break }
+      if (node.label && isBreak) { break }
+    }
+  }
+  if (i === this.labels.length) { this.raise(node.start, "Unsyntactic " + keyword); }
+  return this.finishNode(node, isBreak ? "BreakStatement" : "ContinueStatement")
+};
+
+pp$1.parseDebuggerStatement = function(node) {
+  this.next();
+  this.semicolon();
+  return this.finishNode(node, "DebuggerStatement")
+};
+
+pp$1.parseDoStatement = function(node) {
+  this.next();
+  this.labels.push(loopLabel);
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  this.expect(types._while);
+  node.test = this.parseParenExpression();
+  if (this.options.ecmaVersion >= 6)
+    { this.eat(types.semi); }
+  else
+    { this.semicolon(); }
+  return this.finishNode(node, "DoWhileStatement")
+};
+
+// Disambiguating between a `for` and a `for`/`in` or `for`/`of`
+// loop is non-trivial. Basically, we have to parse the init `var`
+// statement or expression, disallowing the `in` operator (see
+// the second parameter to `parseExpression`), and then check
+// whether the next token is `in` or `of`. When there is no init
+// part (semicolon immediately after the opening parenthesis), it
+// is a regular `for` loop.
+
+pp$1.parseForStatement = function(node) {
+  this.next();
+  this.labels.push(loopLabel);
+  this.enterLexicalScope();
+  this.expect(types.parenL);
+  if (this.type === types.semi) { return this.parseFor(node, null) }
+  var isLet = this.isLet();
+  if (this.type === types._var || this.type === types._const || isLet) {
+    var init$1 = this.startNode(), kind = isLet ? "let" : this.value;
+    this.next();
+    this.parseVar(init$1, true, kind);
+    this.finishNode(init$1, "VariableDeclaration");
+    if ((this.type === types._in || (this.options.ecmaVersion >= 6 && this.isContextual("of"))) && init$1.declarations.length === 1 &&
+        !(kind !== "var" && init$1.declarations[0].init))
+      { return this.parseForIn(node, init$1) }
+    return this.parseFor(node, init$1)
+  }
+  var refDestructuringErrors = new DestructuringErrors;
+  var init = this.parseExpression(true, refDestructuringErrors);
+  if (this.type === types._in || (this.options.ecmaVersion >= 6 && this.isContextual("of"))) {
+    this.toAssignable(init);
+    this.checkLVal(init);
+    this.checkPatternErrors(refDestructuringErrors, true);
+    return this.parseForIn(node, init)
+  } else {
+    this.checkExpressionErrors(refDestructuringErrors, true);
+  }
+  return this.parseFor(node, init)
+};
+
+pp$1.parseFunctionStatement = function(node, isAsync) {
+  this.next();
+  return this.parseFunction(node, true, false, isAsync)
+};
+
+pp$1.isFunction = function() {
+  return this.type === types._function || this.isAsyncFunction()
+};
+
+pp$1.parseIfStatement = function(node) {
+  this.next();
+  node.test = this.parseParenExpression();
+  // allow function declarations in branches, but only in non-strict mode
+  node.consequent = this.parseStatement(!this.strict && this.isFunction());
+  node.alternate = this.eat(types._else) ? this.parseStatement(!this.strict && this.isFunction()) : null;
+  return this.finishNode(node, "IfStatement")
+};
+
+pp$1.parseReturnStatement = function(node) {
+  if (!this.inFunction && !this.options.allowReturnOutsideFunction)
+    { this.raise(this.start, "'return' outside of function"); }
+  this.next();
+
+  // In `return` (and `break`/`continue`), the keywords with
+  // optional arguments, we eagerly look for a semicolon or the
+  // possibility to insert one.
+
+  if (this.eat(types.semi) || this.insertSemicolon()) { node.argument = null; }
+  else { node.argument = this.parseExpression(); this.semicolon(); }
+  return this.finishNode(node, "ReturnStatement")
+};
+
+pp$1.parseSwitchStatement = function(node) {
+  var this$1 = this;
+
+  this.next();
+  node.discriminant = this.parseParenExpression();
+  node.cases = [];
+  this.expect(types.braceL);
+  this.labels.push(switchLabel);
+  this.enterLexicalScope();
+
+  // Statements under must be grouped (by label) in SwitchCase
+  // nodes. `cur` is used to keep the node that we are currently
+  // adding statements to.
+
+  var cur;
+  for (var sawDefault = false; this.type != types.braceR;) {
+    if (this$1.type === types._case || this$1.type === types._default) {
+      var isCase = this$1.type === types._case;
+      if (cur) { this$1.finishNode(cur, "SwitchCase"); }
+      node.cases.push(cur = this$1.startNode());
+      cur.consequent = [];
+      this$1.next();
+      if (isCase) {
+        cur.test = this$1.parseExpression();
+      } else {
+        if (sawDefault) { this$1.raiseRecoverable(this$1.lastTokStart, "Multiple default clauses"); }
+        sawDefault = true;
+        cur.test = null;
+      }
+      this$1.expect(types.colon);
+    } else {
+      if (!cur) { this$1.unexpected(); }
+      cur.consequent.push(this$1.parseStatement(true));
+    }
+  }
+  this.exitLexicalScope();
+  if (cur) { this.finishNode(cur, "SwitchCase"); }
+  this.next(); // Closing brace
+  this.labels.pop();
+  return this.finishNode(node, "SwitchStatement")
+};
+
+pp$1.parseThrowStatement = function(node) {
+  this.next();
+  if (lineBreak.test(this.input.slice(this.lastTokEnd, this.start)))
+    { this.raise(this.lastTokEnd, "Illegal newline after throw"); }
+  node.argument = this.parseExpression();
+  this.semicolon();
+  return this.finishNode(node, "ThrowStatement")
+};
+
+// Reused empty array added for node fields that are always empty.
+
+var empty = [];
+
+pp$1.parseTryStatement = function(node) {
+  this.next();
+  node.block = this.parseBlock();
+  node.handler = null;
+  if (this.type === types._catch) {
+    var clause = this.startNode();
+    this.next();
+    this.expect(types.parenL);
+    clause.param = this.parseBindingAtom();
+    this.enterLexicalScope();
+    this.checkLVal(clause.param, "let");
+    this.expect(types.parenR);
+    clause.body = this.parseBlock(false);
+    this.exitLexicalScope();
+    node.handler = this.finishNode(clause, "CatchClause");
+  }
+  node.finalizer = this.eat(types._finally) ? this.parseBlock() : null;
+  if (!node.handler && !node.finalizer)
+    { this.raise(node.start, "Missing catch or finally clause"); }
+  return this.finishNode(node, "TryStatement")
+};
+
+pp$1.parseVarStatement = function(node, kind) {
+  this.next();
+  this.parseVar(node, false, kind);
+  this.semicolon();
+  return this.finishNode(node, "VariableDeclaration")
+};
+
+pp$1.parseWhileStatement = function(node) {
+  this.next();
+  node.test = this.parseParenExpression();
+  this.labels.push(loopLabel);
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  return this.finishNode(node, "WhileStatement")
+};
+
+pp$1.parseWithStatement = function(node) {
+  if (this.strict) { this.raise(this.start, "'with' in strict mode"); }
+  this.next();
+  node.object = this.parseParenExpression();
+  node.body = this.parseStatement(false);
+  return this.finishNode(node, "WithStatement")
+};
+
+pp$1.parseEmptyStatement = function(node) {
+  this.next();
+  return this.finishNode(node, "EmptyStatement")
+};
+
+pp$1.parseLabeledStatement = function(node, maybeName, expr) {
+  var this$1 = this;
+
+  for (var i$1 = 0, list = this$1.labels; i$1 < list.length; i$1 += 1)
+    {
+    var label = list[i$1];
+
+    if (label.name === maybeName)
+      { this$1.raise(expr.start, "Label '" + maybeName + "' is already declared");
+  } }
+  var kind = this.type.isLoop ? "loop" : this.type === types._switch ? "switch" : null;
+  for (var i = this.labels.length - 1; i >= 0; i--) {
+    var label$1 = this$1.labels[i];
+    if (label$1.statementStart == node.start) {
+      label$1.statementStart = this$1.start;
+      label$1.kind = kind;
+    } else { break }
+  }
+  this.labels.push({name: maybeName, kind: kind, statementStart: this.start});
+  node.body = this.parseStatement(true);
+  if (node.body.type == "ClassDeclaration" ||
+      node.body.type == "VariableDeclaration" && node.body.kind != "var" ||
+      node.body.type == "FunctionDeclaration" && (this.strict || node.body.generator))
+    { this.raiseRecoverable(node.body.start, "Invalid labeled declaration"); }
+  this.labels.pop();
+  node.label = expr;
+  return this.finishNode(node, "LabeledStatement")
+};
+
+pp$1.parseExpressionStatement = function(node, expr) {
+  node.expression = expr;
+  this.semicolon();
+  return this.finishNode(node, "ExpressionStatement")
+};
+
+// Parse a semicolon-enclosed block of statements, handling `"use
+// strict"` declarations when `allowStrict` is true (used for
+// function bodies).
+
+pp$1.parseBlock = function(createNewLexicalScope) {
+  var this$1 = this;
+  if ( createNewLexicalScope === void 0 ) createNewLexicalScope = true;
+
+  var node = this.startNode();
+  node.body = [];
+  this.expect(types.braceL);
+  if (createNewLexicalScope) {
+    this.enterLexicalScope();
+  }
+  while (!this.eat(types.braceR)) {
+    var stmt = this$1.parseStatement(true);
+    node.body.push(stmt);
+  }
+  if (createNewLexicalScope) {
+    this.exitLexicalScope();
+  }
+  return this.finishNode(node, "BlockStatement")
+};
+
+// Parse a regular `for` loop. The disambiguation code in
+// `parseStatement` will already have parsed the init statement or
+// expression.
+
+pp$1.parseFor = function(node, init) {
+  node.init = init;
+  this.expect(types.semi);
+  node.test = this.type === types.semi ? null : this.parseExpression();
+  this.expect(types.semi);
+  node.update = this.type === types.parenR ? null : this.parseExpression();
+  this.expect(types.parenR);
+  this.exitLexicalScope();
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  return this.finishNode(node, "ForStatement")
+};
+
+// Parse a `for`/`in` and `for`/`of` loop, which are almost
+// same from parser's perspective.
+
+pp$1.parseForIn = function(node, init) {
+  var type = this.type === types._in ? "ForInStatement" : "ForOfStatement";
+  this.next();
+  node.left = init;
+  node.right = this.parseExpression();
+  this.expect(types.parenR);
+  this.exitLexicalScope();
+  node.body = this.parseStatement(false);
+  this.labels.pop();
+  return this.finishNode(node, type)
+};
+
+// Parse a list of variable declarations.
+
+pp$1.parseVar = function(node, isFor, kind) {
+  var this$1 = this;
+
+  node.declarations = [];
+  node.kind = kind;
+  for (;;) {
+    var decl = this$1.startNode();
+    this$1.parseVarId(decl, kind);
+    if (this$1.eat(types.eq)) {
+      decl.init = this$1.parseMaybeAssign(isFor);
+    } else if (kind === "const" && !(this$1.type === types._in || (this$1.options.ecmaVersion >= 6 && this$1.isContextual("of")))) {
+      this$1.unexpected();
+    } else if (decl.id.type != "Identifier" && !(isFor && (this$1.type === types._in || this$1.isContextual("of")))) {
+      this$1.raise(this$1.lastTokEnd, "Complex binding patterns require an initialization value");
+    } else {
+      decl.init = null;
+    }
+    node.declarations.push(this$1.finishNode(decl, "VariableDeclarator"));
+    if (!this$1.eat(types.comma)) { break }
+  }
+  return node
+};
+
+pp$1.parseVarId = function(decl, kind) {
+  decl.id = this.parseBindingAtom(kind);
+  this.checkLVal(decl.id, kind, false);
+};
+
+// Parse a function declaration or literal (depending on the
+// `isStatement` parameter).
+
+pp$1.parseFunction = function(node, isStatement, allowExpressionBody, isAsync) {
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 6 && !isAsync)
+    { node.generator = this.eat(types.star); }
+  if (this.options.ecmaVersion >= 8)
+    { node.async = !!isAsync; }
+
+  if (isStatement) {
+    node.id = isStatement === "nullableID" && this.type != types.name ? null : this.parseIdent();
+    if (node.id) {
+      this.checkLVal(node.id, "var");
+    }
+  }
+
+  var oldInGen = this.inGenerator, oldInAsync = this.inAsync,
+      oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos, oldInFunc = this.inFunction;
+  this.inGenerator = node.generator;
+  this.inAsync = node.async;
+  this.yieldPos = 0;
+  this.awaitPos = 0;
+  this.inFunction = true;
+  this.enterFunctionScope();
+
+  if (!isStatement)
+    { node.id = this.type == types.name ? this.parseIdent() : null; }
+
+  this.parseFunctionParams(node);
+  this.parseFunctionBody(node, allowExpressionBody);
+
+  this.inGenerator = oldInGen;
+  this.inAsync = oldInAsync;
+  this.yieldPos = oldYieldPos;
+  this.awaitPos = oldAwaitPos;
+  this.inFunction = oldInFunc;
+  return this.finishNode(node, isStatement ? "FunctionDeclaration" : "FunctionExpression")
+};
+
+pp$1.parseFunctionParams = function(node) {
+  this.expect(types.parenL);
+  node.params = this.parseBindingList(types.parenR, false, this.options.ecmaVersion >= 8);
+  this.checkYieldAwaitInDefaultParams();
+};
+
+// Parse a class declaration or literal (depending on the
+// `isStatement` parameter).
+
+pp$1.parseClass = function(node, isStatement) {
+  var this$1 = this;
+
+  this.next();
+
+  this.parseClassId(node, isStatement);
+  this.parseClassSuper(node);
+  var classBody = this.startNode();
+  var hadConstructor = false;
+  classBody.body = [];
+  this.expect(types.braceL);
+  while (!this.eat(types.braceR)) {
+    if (this$1.eat(types.semi)) { continue }
+    var method = this$1.startNode();
+    var isGenerator = this$1.eat(types.star);
+    var isAsync = false;
+    var isMaybeStatic = this$1.type === types.name && this$1.value === "static";
+    this$1.parsePropertyName(method);
+    method.static = isMaybeStatic && this$1.type !== types.parenL;
+    if (method.static) {
+      if (isGenerator) { this$1.unexpected(); }
+      isGenerator = this$1.eat(types.star);
+      this$1.parsePropertyName(method);
+    }
+    if (this$1.options.ecmaVersion >= 8 && !isGenerator && !method.computed &&
+        method.key.type === "Identifier" && method.key.name === "async" && this$1.type !== types.parenL &&
+        !this$1.canInsertSemicolon()) {
+      isAsync = true;
+      this$1.parsePropertyName(method);
+    }
+    method.kind = "method";
+    var isGetSet = false;
+    if (!method.computed) {
+      var key = method.key;
+      if (!isGenerator && !isAsync && key.type === "Identifier" && this$1.type !== types.parenL && (key.name === "get" || key.name === "set")) {
+        isGetSet = true;
+        method.kind = key.name;
+        key = this$1.parsePropertyName(method);
+      }
+      if (!method.static && (key.type === "Identifier" && key.name === "constructor" ||
+          key.type === "Literal" && key.value === "constructor")) {
+        if (hadConstructor) { this$1.raise(key.start, "Duplicate constructor in the same class"); }
+        if (isGetSet) { this$1.raise(key.start, "Constructor can't have get/set modifier"); }
+        if (isGenerator) { this$1.raise(key.start, "Constructor can't be a generator"); }
+        if (isAsync) { this$1.raise(key.start, "Constructor can't be an async method"); }
+        method.kind = "constructor";
+        hadConstructor = true;
+      }
+    }
+    this$1.parseClassMethod(classBody, method, isGenerator, isAsync);
+    if (isGetSet) {
+      var paramCount = method.kind === "get" ? 0 : 1;
+      if (method.value.params.length !== paramCount) {
+        var start = method.value.start;
+        if (method.kind === "get")
+          { this$1.raiseRecoverable(start, "getter should have no params"); }
+        else
+          { this$1.raiseRecoverable(start, "setter should have exactly one param"); }
+      } else {
+        if (method.kind === "set" && method.value.params[0].type === "RestElement")
+          { this$1.raiseRecoverable(method.value.params[0].start, "Setter cannot use rest params"); }
+      }
+    }
+  }
+  node.body = this.finishNode(classBody, "ClassBody");
+  return this.finishNode(node, isStatement ? "ClassDeclaration" : "ClassExpression")
+};
+
+pp$1.parseClassMethod = function(classBody, method, isGenerator, isAsync) {
+  method.value = this.parseMethod(isGenerator, isAsync);
+  classBody.body.push(this.finishNode(method, "MethodDefinition"));
+};
+
+pp$1.parseClassId = function(node, isStatement) {
+  node.id = this.type === types.name ? this.parseIdent() : isStatement === true ? this.unexpected() : null;
+};
+
+pp$1.parseClassSuper = function(node) {
+  node.superClass = this.eat(types._extends) ? this.parseExprSubscripts() : null;
+};
+
+// Parses module export declaration.
+
+pp$1.parseExport = function(node, exports) {
+  var this$1 = this;
+
+  this.next();
+  // export * from '...'
+  if (this.eat(types.star)) {
+    this.expectContextual("from");
+    node.source = this.type === types.string ? this.parseExprAtom() : this.unexpected();
+    this.semicolon();
+    return this.finishNode(node, "ExportAllDeclaration")
+  }
+  if (this.eat(types._default)) { // export default ...
+    this.checkExport(exports, "default", this.lastTokStart);
+    var isAsync;
+    if (this.type === types._function || (isAsync = this.isAsyncFunction())) {
+      var fNode = this.startNode();
+      this.next();
+      if (isAsync) { this.next(); }
+      node.declaration = this.parseFunction(fNode, "nullableID", false, isAsync);
+    } else if (this.type === types._class) {
+      var cNode = this.startNode();
+      node.declaration = this.parseClass(cNode, "nullableID");
+    } else {
+      node.declaration = this.parseMaybeAssign();
+      this.semicolon();
+    }
+    return this.finishNode(node, "ExportDefaultDeclaration")
+  }
+  // export var|const|let|function|class ...
+  if (this.shouldParseExportStatement()) {
+    node.declaration = this.parseStatement(true);
+    if (node.declaration.type === "VariableDeclaration")
+      { this.checkVariableExport(exports, node.declaration.declarations); }
+    else
+      { this.checkExport(exports, node.declaration.id.name, node.declaration.id.start); }
+    node.specifiers = [];
+    node.source = null;
+  } else { // export { x, y as z } [from '...']
+    node.declaration = null;
+    node.specifiers = this.parseExportSpecifiers(exports);
+    if (this.eatContextual("from")) {
+      node.source = this.type === types.string ? this.parseExprAtom() : this.unexpected();
+    } else {
+      // check for keywords used as local names
+      for (var i = 0, list = node.specifiers; i < list.length; i += 1) {
+        var spec = list[i];
+
+        this$1.checkUnreserved(spec.local);
+      }
+
+      node.source = null;
+    }
+    this.semicolon();
+  }
+  return this.finishNode(node, "ExportNamedDeclaration")
+};
+
+pp$1.checkExport = function(exports, name, pos) {
+  if (!exports) { return }
+  if (has(exports, name))
+    { this.raiseRecoverable(pos, "Duplicate export '" + name + "'"); }
+  exports[name] = true;
+};
+
+pp$1.checkPatternExport = function(exports, pat) {
+  var this$1 = this;
+
+  var type = pat.type;
+  if (type == "Identifier")
+    { this.checkExport(exports, pat.name, pat.start); }
+  else if (type == "ObjectPattern")
+    { for (var i = 0, list = pat.properties; i < list.length; i += 1)
+      {
+        var prop = list[i];
+
+        this$1.checkPatternExport(exports, prop.value);
+      } }
+  else if (type == "ArrayPattern")
+    { for (var i$1 = 0, list$1 = pat.elements; i$1 < list$1.length; i$1 += 1) {
+      var elt = list$1[i$1];
+
+        if (elt) { this$1.checkPatternExport(exports, elt); }
+    } }
+  else if (type == "AssignmentPattern")
+    { this.checkPatternExport(exports, pat.left); }
+  else if (type == "ParenthesizedExpression")
+    { this.checkPatternExport(exports, pat.expression); }
+};
+
+pp$1.checkVariableExport = function(exports, decls) {
+  var this$1 = this;
+
+  if (!exports) { return }
+  for (var i = 0, list = decls; i < list.length; i += 1)
+    {
+    var decl = list[i];
+
+    this$1.checkPatternExport(exports, decl.id);
+  }
+};
+
+pp$1.shouldParseExportStatement = function() {
+  return this.type.keyword === "var" ||
+    this.type.keyword === "const" ||
+    this.type.keyword === "class" ||
+    this.type.keyword === "function" ||
+    this.isLet() ||
+    this.isAsyncFunction()
+};
+
+// Parses a comma-separated list of module exports.
+
+pp$1.parseExportSpecifiers = function(exports) {
+  var this$1 = this;
+
+  var nodes = [], first = true;
+  // export { x, y as z } [from '...']
+  this.expect(types.braceL);
+  while (!this.eat(types.braceR)) {
+    if (!first) {
+      this$1.expect(types.comma);
+      if (this$1.afterTrailingComma(types.braceR)) { break }
+    } else { first = false; }
+
+    var node = this$1.startNode();
+    node.local = this$1.parseIdent(true);
+    node.exported = this$1.eatContextual("as") ? this$1.parseIdent(true) : node.local;
+    this$1.checkExport(exports, node.exported.name, node.exported.start);
+    nodes.push(this$1.finishNode(node, "ExportSpecifier"));
+  }
+  return nodes
+};
+
+// Parses import declaration.
+
+pp$1.parseImport = function(node) {
+  this.next();
+  // import '...'
+  if (this.type === types.string) {
+    node.specifiers = empty;
+    node.source = this.parseExprAtom();
+  } else {
+    node.specifiers = this.parseImportSpecifiers();
+    this.expectContextual("from");
+    node.source = this.type === types.string ? this.parseExprAtom() : this.unexpected();
+  }
+  this.semicolon();
+  return this.finishNode(node, "ImportDeclaration")
+};
+
+// Parses a comma-separated list of module imports.
+
+pp$1.parseImportSpecifiers = function() {
+  var this$1 = this;
+
+  var nodes = [], first = true;
+  if (this.type === types.name) {
+    // import defaultObj, { x, y as z } from '...'
+    var node = this.startNode();
+    node.local = this.parseIdent();
+    this.checkLVal(node.local, "let");
+    nodes.push(this.finishNode(node, "ImportDefaultSpecifier"));
+    if (!this.eat(types.comma)) { return nodes }
+  }
+  if (this.type === types.star) {
+    var node$1 = this.startNode();
+    this.next();
+    this.expectContextual("as");
+    node$1.local = this.parseIdent();
+    this.checkLVal(node$1.local, "let");
+    nodes.push(this.finishNode(node$1, "ImportNamespaceSpecifier"));
+    return nodes
+  }
+  this.expect(types.braceL);
+  while (!this.eat(types.braceR)) {
+    if (!first) {
+      this$1.expect(types.comma);
+      if (this$1.afterTrailingComma(types.braceR)) { break }
+    } else { first = false; }
+
+    var node$2 = this$1.startNode();
+    node$2.imported = this$1.parseIdent(true);
+    if (this$1.eatContextual("as")) {
+      node$2.local = this$1.parseIdent();
+    } else {
+      this$1.checkUnreserved(node$2.imported);
+      node$2.local = node$2.imported;
+    }
+    this$1.checkLVal(node$2.local, "let");
+    nodes.push(this$1.finishNode(node$2, "ImportSpecifier"));
+  }
+  return nodes
+};
+
+// Set `ExpressionStatement#directive` property for directive prologues.
+pp$1.adaptDirectivePrologue = function(statements) {
+  for (var i = 0; i < statements.length && this.isDirectiveCandidate(statements[i]); ++i) {
+    statements[i].directive = statements[i].expression.raw.slice(1, -1);
+  }
+};
+pp$1.isDirectiveCandidate = function(statement) {
+  return (
+    statement.type === "ExpressionStatement" &&
+    statement.expression.type === "Literal" &&
+    typeof statement.expression.value === "string" &&
+    // Reject parenthesized strings.
+    (this.input[statement.start] === "\"" || this.input[statement.start] === "'")
+  )
+};
+
+var pp$2 = Parser.prototype;
+
+// Convert existing expression atom to assignable pattern
+// if possible.
+
+pp$2.toAssignable = function(node, isBinding) {
+  var this$1 = this;
+
+  if (this.options.ecmaVersion >= 6 && node) {
+    switch (node.type) {
+    case "Identifier":
+      if (this.inAsync && node.name === "await")
+        { this.raise(node.start, "Can not use 'await' as identifier inside an async function"); }
+      break
+
+    case "ObjectPattern":
+    case "ArrayPattern":
+      break
+
+    case "ObjectExpression":
+      node.type = "ObjectPattern";
+      for (var i = 0, list = node.properties; i < list.length; i += 1) {
+        var prop = list[i];
+
+      if (prop.kind !== "init") { this$1.raise(prop.key.start, "Object pattern can't contain getter or setter"); }
+        this$1.toAssignable(prop.value, isBinding);
+      }
+      break
+
+    case "ArrayExpression":
+      node.type = "ArrayPattern";
+      this.toAssignableList(node.elements, isBinding);
+      break
+
+    case "AssignmentExpression":
+      if (node.operator === "=") {
+        node.type = "AssignmentPattern";
+        delete node.operator;
+        this.toAssignable(node.left, isBinding);
+        // falls through to AssignmentPattern
+      } else {
+        this.raise(node.left.end, "Only '=' operator can be used for specifying default value.");
+        break
+      }
+
+    case "AssignmentPattern":
+      break
+
+    case "ParenthesizedExpression":
+      this.toAssignable(node.expression, isBinding);
+      break
+
+    case "MemberExpression":
+      if (!isBinding) { break }
+
+    default:
+      this.raise(node.start, "Assigning to rvalue");
+    }
+  }
+  return node
+};
+
+// Convert list of expression atoms to binding list.
+
+pp$2.toAssignableList = function(exprList, isBinding) {
+  var this$1 = this;
+
+  var end = exprList.length;
+  if (end) {
+    var last = exprList[end - 1];
+    if (last && last.type == "RestElement") {
+      --end;
+    } else if (last && last.type == "SpreadElement") {
+      last.type = "RestElement";
+      var arg = last.argument;
+      this.toAssignable(arg, isBinding);
+      --end;
+    }
+
+    if (this.options.ecmaVersion === 6 && isBinding && last && last.type === "RestElement" && last.argument.type !== "Identifier")
+      { this.unexpected(last.argument.start); }
+  }
+  for (var i = 0; i < end; i++) {
+    var elt = exprList[i];
+    if (elt) { this$1.toAssignable(elt, isBinding); }
+  }
+  return exprList
+};
+
+// Parses spread element.
+
+pp$2.parseSpread = function(refDestructuringErrors) {
+  var node = this.startNode();
+  this.next();
+  node.argument = this.parseMaybeAssign(false, refDestructuringErrors);
+  return this.finishNode(node, "SpreadElement")
+};
+
+pp$2.parseRestBinding = function() {
+  var node = this.startNode();
+  this.next();
+
+  // RestElement inside of a function parameter must be an identifier
+  if (this.options.ecmaVersion === 6 && this.type !== types.name)
+    { this.unexpected(); }
+
+  node.argument = this.parseBindingAtom();
+
+  return this.finishNode(node, "RestElement")
+};
+
+// Parses lvalue (assignable) atom.
+
+pp$2.parseBindingAtom = function() {
+  if (this.options.ecmaVersion >= 6) {
+    switch (this.type) {
+    case types.bracketL:
+      var node = this.startNode();
+      this.next();
+      node.elements = this.parseBindingList(types.bracketR, true, true);
+      return this.finishNode(node, "ArrayPattern")
+
+    case types.braceL:
+      return this.parseObj(true)
+    }
+  }
+  return this.parseIdent()
+};
+
+pp$2.parseBindingList = function(close, allowEmpty, allowTrailingComma) {
+  var this$1 = this;
+
+  var elts = [], first = true;
+  while (!this.eat(close)) {
+    if (first) { first = false; }
+    else { this$1.expect(types.comma); }
+    if (allowEmpty && this$1.type === types.comma) {
+      elts.push(null);
+    } else if (allowTrailingComma && this$1.afterTrailingComma(close)) {
+      break
+    } else if (this$1.type === types.ellipsis) {
+      var rest = this$1.parseRestBinding();
+      this$1.parseBindingListItem(rest);
+      elts.push(rest);
+      if (this$1.type === types.comma) { this$1.raise(this$1.start, "Comma is not permitted after the rest element"); }
+      this$1.expect(close);
+      break
+    } else {
+      var elem = this$1.parseMaybeDefault(this$1.start, this$1.startLoc);
+      this$1.parseBindingListItem(elem);
+      elts.push(elem);
+    }
+  }
+  return elts
+};
+
+pp$2.parseBindingListItem = function(param) {
+  return param
+};
+
+// Parses assignment pattern around given atom if possible.
+
+pp$2.parseMaybeDefault = function(startPos, startLoc, left) {
+  left = left || this.parseBindingAtom();
+  if (this.options.ecmaVersion < 6 || !this.eat(types.eq)) { return left }
+  var node = this.startNodeAt(startPos, startLoc);
+  node.left = left;
+  node.right = this.parseMaybeAssign();
+  return this.finishNode(node, "AssignmentPattern")
+};
+
+// Verify that a node is an lval — something that can be assigned
+// to.
+// bindingType can be either:
+// 'var' indicating that the lval creates a 'var' binding
+// 'let' indicating that the lval creates a lexical ('let' or 'const') binding
+// 'none' indicating that the binding should be checked for illegal identifiers, but not for duplicate references
+
+pp$2.checkLVal = function(expr, bindingType, checkClashes) {
+  var this$1 = this;
+
+  switch (expr.type) {
+  case "Identifier":
+    if (this.strict && this.reservedWordsStrictBind.test(expr.name))
+      { this.raiseRecoverable(expr.start, (bindingType ? "Binding " : "Assigning to ") + expr.name + " in strict mode"); }
+    if (checkClashes) {
+      if (has(checkClashes, expr.name))
+        { this.raiseRecoverable(expr.start, "Argument name clash"); }
+      checkClashes[expr.name] = true;
+    }
+    if (bindingType && bindingType !== "none") {
+      if (
+        bindingType === "var" && !this.canDeclareVarName(expr.name) ||
+        bindingType !== "var" && !this.canDeclareLexicalName(expr.name)
+      ) {
+        this.raiseRecoverable(expr.start, ("Identifier '" + (expr.name) + "' has already been declared"));
+      }
+      if (bindingType === "var") {
+        this.declareVarName(expr.name);
+      } else {
+        this.declareLexicalName(expr.name);
+      }
+    }
+    break
+
+  case "MemberExpression":
+    if (bindingType) { this.raiseRecoverable(expr.start, (bindingType ? "Binding" : "Assigning to") + " member expression"); }
+    break
+
+  case "ObjectPattern":
+    for (var i = 0, list = expr.properties; i < list.length; i += 1)
+      {
+    var prop = list[i];
+
+    this$1.checkLVal(prop.value, bindingType, checkClashes);
+  }
+    break
+
+  case "ArrayPattern":
+    for (var i$1 = 0, list$1 = expr.elements; i$1 < list$1.length; i$1 += 1) {
+      var elem = list$1[i$1];
+
+    if (elem) { this$1.checkLVal(elem, bindingType, checkClashes); }
+    }
+    break
+
+  case "AssignmentPattern":
+    this.checkLVal(expr.left, bindingType, checkClashes);
+    break
+
+  case "RestElement":
+    this.checkLVal(expr.argument, bindingType, checkClashes);
+    break
+
+  case "ParenthesizedExpression":
+    this.checkLVal(expr.expression, bindingType, checkClashes);
+    break
+
+  default:
+    this.raise(expr.start, (bindingType ? "Binding" : "Assigning to") + " rvalue");
+  }
+};
+
+// A recursive descent parser operates by defining functions for all
+// syntactic elements, and recursively calling those, each function
+// advancing the input stream and returning an AST node. Precedence
+// of constructs (for example, the fact that `!x[1]` means `!(x[1])`
+// instead of `(!x)[1]` is handled by the fact that the parser
+// function that parses unary prefix operators is called first, and
+// in turn calls the function that parses `[]` subscripts — that
+// way, it'll receive the node for `x[1]` already parsed, and wraps
+// *that* in the unary operator node.
+//
+// Acorn uses an [operator precedence parser][opp] to handle binary
+// operator precedence, because it is much more compact than using
+// the technique outlined above, which uses different, nesting
+// functions to specify precedence, for all of the ten binary
+// precedence levels that JavaScript defines.
+//
+// [opp]: http://en.wikipedia.org/wiki/Operator-precedence_parser
+
+var pp$3 = Parser.prototype;
+
+// Check if property name clashes with already added.
+// Object/class getters and setters are not allowed to clash —
+// either with each other or with an init property — and in
+// strict mode, init properties are also not allowed to be repeated.
+
+pp$3.checkPropClash = function(prop, propHash) {
+  if (this.options.ecmaVersion >= 6 && (prop.computed || prop.method || prop.shorthand))
+    { return }
+  var key = prop.key;
+  var name;
+  switch (key.type) {
+  case "Identifier": name = key.name; break
+  case "Literal": name = String(key.value); break
+  default: return
+  }
+  var kind = prop.kind;
+  if (this.options.ecmaVersion >= 6) {
+    if (name === "__proto__" && kind === "init") {
+      if (propHash.proto) { this.raiseRecoverable(key.start, "Redefinition of __proto__ property"); }
+      propHash.proto = true;
+    }
+    return
+  }
+  name = "$" + name;
+  var other = propHash[name];
+  if (other) {
+    var redefinition;
+    if (kind === "init") {
+      redefinition = this.strict && other.init || other.get || other.set;
+    } else {
+      redefinition = other.init || other[kind];
+    }
+    if (redefinition)
+      { this.raiseRecoverable(key.start, "Redefinition of property"); }
+  } else {
+    other = propHash[name] = {
+      init: false,
+      get: false,
+      set: false
+    };
+  }
+  other[kind] = true;
+};
+
+// ### Expression parsing
+
+// These nest, from the most general expression type at the top to
+// 'atomic', nondivisible expression types at the bottom. Most of
+// the functions will simply let the function(s) below them parse,
+// and, *if* the syntactic construct they handle is present, wrap
+// the AST node that the inner parser gave them in another node.
+
+// Parse a full expression. The optional arguments are used to
+// forbid the `in` operator (in for loops initalization expressions)
+// and provide reference for storing '=' operator inside shorthand
+// property assignment in contexts where both object expression
+// and object pattern might appear (so it's possible to raise
+// delayed syntax error at correct position).
+
+pp$3.parseExpression = function(noIn, refDestructuringErrors) {
+  var this$1 = this;
+
+  var startPos = this.start, startLoc = this.startLoc;
+  var expr = this.parseMaybeAssign(noIn, refDestructuringErrors);
+  if (this.type === types.comma) {
+    var node = this.startNodeAt(startPos, startLoc);
+    node.expressions = [expr];
+    while (this.eat(types.comma)) { node.expressions.push(this$1.parseMaybeAssign(noIn, refDestructuringErrors)); }
+    return this.finishNode(node, "SequenceExpression")
+  }
+  return expr
+};
+
+// Parse an assignment expression. This includes applications of
+// operators like `+=`.
+
+pp$3.parseMaybeAssign = function(noIn, refDestructuringErrors, afterLeftParse) {
+  if (this.inGenerator && this.isContextual("yield")) { return this.parseYield() }
+
+  var ownDestructuringErrors = false, oldParenAssign = -1, oldTrailingComma = -1;
+  if (refDestructuringErrors) {
+    oldParenAssign = refDestructuringErrors.parenthesizedAssign;
+    oldTrailingComma = refDestructuringErrors.trailingComma;
+    refDestructuringErrors.parenthesizedAssign = refDestructuringErrors.trailingComma = -1;
+  } else {
+    refDestructuringErrors = new DestructuringErrors;
+    ownDestructuringErrors = true;
+  }
+
+  var startPos = this.start, startLoc = this.startLoc;
+  if (this.type == types.parenL || this.type == types.name)
+    { this.potentialArrowAt = this.start; }
+  var left = this.parseMaybeConditional(noIn, refDestructuringErrors);
+  if (afterLeftParse) { left = afterLeftParse.call(this, left, startPos, startLoc); }
+  if (this.type.isAssign) {
+    this.checkPatternErrors(refDestructuringErrors, true);
+    if (!ownDestructuringErrors) { DestructuringErrors.call(refDestructuringErrors); }
+    var node = this.startNodeAt(startPos, startLoc);
+    node.operator = this.value;
+    node.left = this.type === types.eq ? this.toAssignable(left) : left;
+    refDestructuringErrors.shorthandAssign = -1; // reset because shorthand default was used correctly
+    this.checkLVal(left);
+    this.next();
+    node.right = this.parseMaybeAssign(noIn);
+    return this.finishNode(node, "AssignmentExpression")
+  } else {
+    if (ownDestructuringErrors) { this.checkExpressionErrors(refDestructuringErrors, true); }
+  }
+  if (oldParenAssign > -1) { refDestructuringErrors.parenthesizedAssign = oldParenAssign; }
+  if (oldTrailingComma > -1) { refDestructuringErrors.trailingComma = oldTrailingComma; }
+  return left
+};
+
+// Parse a ternary conditional (`?:`) operator.
+
+pp$3.parseMaybeConditional = function(noIn, refDestructuringErrors) {
+  var startPos = this.start, startLoc = this.startLoc;
+  var expr = this.parseExprOps(noIn, refDestructuringErrors);
+  if (this.checkExpressionErrors(refDestructuringErrors)) { return expr }
+  if (this.eat(types.question)) {
+    var node = this.startNodeAt(startPos, startLoc);
+    node.test = expr;
+    node.consequent = this.parseMaybeAssign();
+    this.expect(types.colon);
+    node.alternate = this.parseMaybeAssign(noIn);
+    return this.finishNode(node, "ConditionalExpression")
+  }
+  return expr
+};
+
+// Start the precedence parser.
+
+pp$3.parseExprOps = function(noIn, refDestructuringErrors) {
+  var startPos = this.start, startLoc = this.startLoc;
+  var expr = this.parseMaybeUnary(refDestructuringErrors, false);
+  if (this.checkExpressionErrors(refDestructuringErrors)) { return expr }
+  return expr.start == startPos && expr.type === "ArrowFunctionExpression" ? expr : this.parseExprOp(expr, startPos, startLoc, -1, noIn)
+};
+
+// Parse binary operators with the operator precedence parsing
+// algorithm. `left` is the left-hand side of the operator.
+// `minPrec` provides context that allows the function to stop and
+// defer further parser to one of its callers when it encounters an
+// operator that has a lower precedence than the set it is parsing.
+
+pp$3.parseExprOp = function(left, leftStartPos, leftStartLoc, minPrec, noIn) {
+  var prec = this.type.binop;
+  if (prec != null && (!noIn || this.type !== types._in)) {
+    if (prec > minPrec) {
+      var logical = this.type === types.logicalOR || this.type === types.logicalAND;
+      var op = this.value;
+      this.next();
+      var startPos = this.start, startLoc = this.startLoc;
+      var right = this.parseExprOp(this.parseMaybeUnary(null, false), startPos, startLoc, prec, noIn);
+      var node = this.buildBinary(leftStartPos, leftStartLoc, left, right, op, logical);
+      return this.parseExprOp(node, leftStartPos, leftStartLoc, minPrec, noIn)
+    }
+  }
+  return left
+};
+
+pp$3.buildBinary = function(startPos, startLoc, left, right, op, logical) {
+  var node = this.startNodeAt(startPos, startLoc);
+  node.left = left;
+  node.operator = op;
+  node.right = right;
+  return this.finishNode(node, logical ? "LogicalExpression" : "BinaryExpression")
+};
+
+// Parse unary operators, both prefix and postfix.
+
+pp$3.parseMaybeUnary = function(refDestructuringErrors, sawUnary) {
+  var this$1 = this;
+
+  var startPos = this.start, startLoc = this.startLoc, expr;
+  if (this.inAsync && this.isContextual("await")) {
+    expr = this.parseAwait();
+    sawUnary = true;
+  } else if (this.type.prefix) {
+    var node = this.startNode(), update = this.type === types.incDec;
+    node.operator = this.value;
+    node.prefix = true;
+    this.next();
+    node.argument = this.parseMaybeUnary(null, true);
+    this.checkExpressionErrors(refDestructuringErrors, true);
+    if (update) { this.checkLVal(node.argument); }
+    else if (this.strict && node.operator === "delete" &&
+             node.argument.type === "Identifier")
+      { this.raiseRecoverable(node.start, "Deleting local variable in strict mode"); }
+    else { sawUnary = true; }
+    expr = this.finishNode(node, update ? "UpdateExpression" : "UnaryExpression");
+  } else {
+    expr = this.parseExprSubscripts(refDestructuringErrors);
+    if (this.checkExpressionErrors(refDestructuringErrors)) { return expr }
+    while (this.type.postfix && !this.canInsertSemicolon()) {
+      var node$1 = this$1.startNodeAt(startPos, startLoc);
+      node$1.operator = this$1.value;
+      node$1.prefix = false;
+      node$1.argument = expr;
+      this$1.checkLVal(expr);
+      this$1.next();
+      expr = this$1.finishNode(node$1, "UpdateExpression");
+    }
+  }
+
+  if (!sawUnary && this.eat(types.starstar))
+    { return this.buildBinary(startPos, startLoc, expr, this.parseMaybeUnary(null, false), "**", false) }
+  else
+    { return expr }
+};
+
+// Parse call, dot, and `[]`-subscript expressions.
+
+pp$3.parseExprSubscripts = function(refDestructuringErrors) {
+  var startPos = this.start, startLoc = this.startLoc;
+  var expr = this.parseExprAtom(refDestructuringErrors);
+  var skipArrowSubscripts = expr.type === "ArrowFunctionExpression" && this.input.slice(this.lastTokStart, this.lastTokEnd) !== ")";
+  if (this.checkExpressionErrors(refDestructuringErrors) || skipArrowSubscripts) { return expr }
+  var result = this.parseSubscripts(expr, startPos, startLoc);
+  if (refDestructuringErrors && result.type === "MemberExpression") {
+    if (refDestructuringErrors.parenthesizedAssign >= result.start) { refDestructuringErrors.parenthesizedAssign = -1; }
+    if (refDestructuringErrors.parenthesizedBind >= result.start) { refDestructuringErrors.parenthesizedBind = -1; }
+  }
+  return result
+};
+
+pp$3.parseSubscripts = function(base, startPos, startLoc, noCalls) {
+  var this$1 = this;
+
+  var maybeAsyncArrow = this.options.ecmaVersion >= 8 && base.type === "Identifier" && base.name === "async" &&
+      this.lastTokEnd == base.end && !this.canInsertSemicolon();
+  for (var computed = (void 0);;) {
+    if ((computed = this$1.eat(types.bracketL)) || this$1.eat(types.dot)) {
+      var node = this$1.startNodeAt(startPos, startLoc);
+      node.object = base;
+      node.property = computed ? this$1.parseExpression() : this$1.parseIdent(true);
+      node.computed = !!computed;
+      if (computed) { this$1.expect(types.bracketR); }
+      base = this$1.finishNode(node, "MemberExpression");
+    } else if (!noCalls && this$1.eat(types.parenL)) {
+      var refDestructuringErrors = new DestructuringErrors, oldYieldPos = this$1.yieldPos, oldAwaitPos = this$1.awaitPos;
+      this$1.yieldPos = 0;
+      this$1.awaitPos = 0;
+      var exprList = this$1.parseExprList(types.parenR, this$1.options.ecmaVersion >= 8, false, refDestructuringErrors);
+      if (maybeAsyncArrow && !this$1.canInsertSemicolon() && this$1.eat(types.arrow)) {
+        this$1.checkPatternErrors(refDestructuringErrors, false);
+        this$1.checkYieldAwaitInDefaultParams();
+        this$1.yieldPos = oldYieldPos;
+        this$1.awaitPos = oldAwaitPos;
+        return this$1.parseArrowExpression(this$1.startNodeAt(startPos, startLoc), exprList, true)
+      }
+      this$1.checkExpressionErrors(refDestructuringErrors, true);
+      this$1.yieldPos = oldYieldPos || this$1.yieldPos;
+      this$1.awaitPos = oldAwaitPos || this$1.awaitPos;
+      var node$1 = this$1.startNodeAt(startPos, startLoc);
+      node$1.callee = base;
+      node$1.arguments = exprList;
+      base = this$1.finishNode(node$1, "CallExpression");
+    } else if (this$1.type === types.backQuote) {
+      var node$2 = this$1.startNodeAt(startPos, startLoc);
+      node$2.tag = base;
+      node$2.quasi = this$1.parseTemplate({isTagged: true});
+      base = this$1.finishNode(node$2, "TaggedTemplateExpression");
+    } else {
+      return base
+    }
+  }
+};
+
+// Parse an atomic expression — either a single token that is an
+// expression, an expression started by a keyword like `function` or
+// `new`, or an expression wrapped in punctuation like `()`, `[]`,
+// or `{}`.
+
+pp$3.parseExprAtom = function(refDestructuringErrors) {
+  var node, canBeArrow = this.potentialArrowAt == this.start;
+  switch (this.type) {
+  case types._super:
+    if (!this.inFunction)
+      { this.raise(this.start, "'super' outside of function or class"); }
+    node = this.startNode();
+    this.next();
+    // The `super` keyword can appear at below:
+    // SuperProperty:
+    //     super [ Expression ]
+    //     super . IdentifierName
+    // SuperCall:
+    //     super Arguments
+    if (this.type !== types.dot && this.type !== types.bracketL && this.type !== types.parenL)
+      { this.unexpected(); }
+    return this.finishNode(node, "Super")
+
+  case types._this:
+    node = this.startNode();
+    this.next();
+    return this.finishNode(node, "ThisExpression")
+
+  case types.name:
+    var startPos = this.start, startLoc = this.startLoc;
+    var id = this.parseIdent(this.type !== types.name);
+    if (this.options.ecmaVersion >= 8 && id.name === "async" && !this.canInsertSemicolon() && this.eat(types._function))
+      { return this.parseFunction(this.startNodeAt(startPos, startLoc), false, false, true) }
+    if (canBeArrow && !this.canInsertSemicolon()) {
+      if (this.eat(types.arrow))
+        { return this.parseArrowExpression(this.startNodeAt(startPos, startLoc), [id], false) }
+      if (this.options.ecmaVersion >= 8 && id.name === "async" && this.type === types.name) {
+        id = this.parseIdent();
+        if (this.canInsertSemicolon() || !this.eat(types.arrow))
+          { this.unexpected(); }
+        return this.parseArrowExpression(this.startNodeAt(startPos, startLoc), [id], true)
+      }
+    }
+    return id
+
+  case types.regexp:
+    var value = this.value;
+    node = this.parseLiteral(value.value);
+    node.regex = {pattern: value.pattern, flags: value.flags};
+    return node
+
+  case types.num: case types.string:
+    return this.parseLiteral(this.value)
+
+  case types._null: case types._true: case types._false:
+    node = this.startNode();
+    node.value = this.type === types._null ? null : this.type === types._true;
+    node.raw = this.type.keyword;
+    this.next();
+    return this.finishNode(node, "Literal")
+
+  case types.parenL:
+    var start = this.start, expr = this.parseParenAndDistinguishExpression(canBeArrow);
+    if (refDestructuringErrors) {
+      if (refDestructuringErrors.parenthesizedAssign < 0 && !this.isSimpleAssignTarget(expr))
+        { refDestructuringErrors.parenthesizedAssign = start; }
+      if (refDestructuringErrors.parenthesizedBind < 0)
+        { refDestructuringErrors.parenthesizedBind = start; }
+    }
+    return expr
+
+  case types.bracketL:
+    node = this.startNode();
+    this.next();
+    node.elements = this.parseExprList(types.bracketR, true, true, refDestructuringErrors);
+    return this.finishNode(node, "ArrayExpression")
+
+  case types.braceL:
+    return this.parseObj(false, refDestructuringErrors)
+
+  case types._function:
+    node = this.startNode();
+    this.next();
+    return this.parseFunction(node, false)
+
+  case types._class:
+    return this.parseClass(this.startNode(), false)
+
+  case types._new:
+    return this.parseNew()
+
+  case types.backQuote:
+    return this.parseTemplate()
+
+  default:
+    this.unexpected();
+  }
+};
+
+pp$3.parseLiteral = function(value) {
+  var node = this.startNode();
+  node.value = value;
+  node.raw = this.input.slice(this.start, this.end);
+  this.next();
+  return this.finishNode(node, "Literal")
+};
+
+pp$3.parseParenExpression = function() {
+  this.expect(types.parenL);
+  var val = this.parseExpression();
+  this.expect(types.parenR);
+  return val
+};
+
+pp$3.parseParenAndDistinguishExpression = function(canBeArrow) {
+  var this$1 = this;
+
+  var startPos = this.start, startLoc = this.startLoc, val, allowTrailingComma = this.options.ecmaVersion >= 8;
+  if (this.options.ecmaVersion >= 6) {
+    this.next();
+
+    var innerStartPos = this.start, innerStartLoc = this.startLoc;
+    var exprList = [], first = true, lastIsComma = false;
+    var refDestructuringErrors = new DestructuringErrors, oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos, spreadStart, innerParenStart;
+    this.yieldPos = 0;
+    this.awaitPos = 0;
+    while (this.type !== types.parenR) {
+      first ? first = false : this$1.expect(types.comma);
+      if (allowTrailingComma && this$1.afterTrailingComma(types.parenR, true)) {
+        lastIsComma = true;
+        break
+      } else if (this$1.type === types.ellipsis) {
+        spreadStart = this$1.start;
+        exprList.push(this$1.parseParenItem(this$1.parseRestBinding()));
+        if (this$1.type === types.comma) { this$1.raise(this$1.start, "Comma is not permitted after the rest element"); }
+        break
+      } else {
+        if (this$1.type === types.parenL && !innerParenStart) {
+          innerParenStart = this$1.start;
+        }
+        exprList.push(this$1.parseMaybeAssign(false, refDestructuringErrors, this$1.parseParenItem));
+      }
+    }
+    var innerEndPos = this.start, innerEndLoc = this.startLoc;
+    this.expect(types.parenR);
+
+    if (canBeArrow && !this.canInsertSemicolon() && this.eat(types.arrow)) {
+      this.checkPatternErrors(refDestructuringErrors, false);
+      this.checkYieldAwaitInDefaultParams();
+      if (innerParenStart) { this.unexpected(innerParenStart); }
+      this.yieldPos = oldYieldPos;
+      this.awaitPos = oldAwaitPos;
+      return this.parseParenArrowList(startPos, startLoc, exprList)
+    }
+
+    if (!exprList.length || lastIsComma) { this.unexpected(this.lastTokStart); }
+    if (spreadStart) { this.unexpected(spreadStart); }
+    this.checkExpressionErrors(refDestructuringErrors, true);
+    this.yieldPos = oldYieldPos || this.yieldPos;
+    this.awaitPos = oldAwaitPos || this.awaitPos;
+
+    if (exprList.length > 1) {
+      val = this.startNodeAt(innerStartPos, innerStartLoc);
+      val.expressions = exprList;
+      this.finishNodeAt(val, "SequenceExpression", innerEndPos, innerEndLoc);
+    } else {
+      val = exprList[0];
+    }
+  } else {
+    val = this.parseParenExpression();
+  }
+
+  if (this.options.preserveParens) {
+    var par = this.startNodeAt(startPos, startLoc);
+    par.expression = val;
+    return this.finishNode(par, "ParenthesizedExpression")
+  } else {
+    return val
+  }
+};
+
+pp$3.parseParenItem = function(item) {
+  return item
+};
+
+pp$3.parseParenArrowList = function(startPos, startLoc, exprList) {
+  return this.parseArrowExpression(this.startNodeAt(startPos, startLoc), exprList)
+};
+
+// New's precedence is slightly tricky. It must allow its argument to
+// be a `[]` or dot subscript expression, but not a call — at least,
+// not without wrapping it in parentheses. Thus, it uses the noCalls
+// argument to parseSubscripts to prevent it from consuming the
+// argument list.
+
+var empty$1 = [];
+
+pp$3.parseNew = function() {
+  var node = this.startNode();
+  var meta = this.parseIdent(true);
+  if (this.options.ecmaVersion >= 6 && this.eat(types.dot)) {
+    node.meta = meta;
+    node.property = this.parseIdent(true);
+    if (node.property.name !== "target")
+      { this.raiseRecoverable(node.property.start, "The only valid meta property for new is new.target"); }
+    if (!this.inFunction)
+      { this.raiseRecoverable(node.start, "new.target can only be used in functions"); }
+    return this.finishNode(node, "MetaProperty")
+  }
+  var startPos = this.start, startLoc = this.startLoc;
+  node.callee = this.parseSubscripts(this.parseExprAtom(), startPos, startLoc, true);
+  if (this.eat(types.parenL)) { node.arguments = this.parseExprList(types.parenR, this.options.ecmaVersion >= 8, false); }
+  else { node.arguments = empty$1; }
+  return this.finishNode(node, "NewExpression")
+};
+
+// Parse template expression.
+
+pp$3.parseTemplateElement = function(ref) {
+  var isTagged = ref.isTagged;
+
+  var elem = this.startNode();
+  if (this.type === types.invalidTemplate) {
+    if (!isTagged) {
+      this.raiseRecoverable(this.start, "Bad escape sequence in untagged template literal");
+    }
+    elem.value = {
+      raw: this.value,
+      cooked: null
+    };
+  } else {
+    elem.value = {
+      raw: this.input.slice(this.start, this.end).replace(/\r\n?/g, "\n"),
+      cooked: this.value
+    };
+  }
+  this.next();
+  elem.tail = this.type === types.backQuote;
+  return this.finishNode(elem, "TemplateElement")
+};
+
+pp$3.parseTemplate = function(ref) {
+  var this$1 = this;
+  if ( ref === void 0 ) ref = {};
+  var isTagged = ref.isTagged; if ( isTagged === void 0 ) isTagged = false;
+
+  var node = this.startNode();
+  this.next();
+  node.expressions = [];
+  var curElt = this.parseTemplateElement({isTagged: isTagged});
+  node.quasis = [curElt];
+  while (!curElt.tail) {
+    this$1.expect(types.dollarBraceL);
+    node.expressions.push(this$1.parseExpression());
+    this$1.expect(types.braceR);
+    node.quasis.push(curElt = this$1.parseTemplateElement({isTagged: isTagged}));
+  }
+  this.next();
+  return this.finishNode(node, "TemplateLiteral")
+};
+
+pp$3.isAsyncProp = function(prop) {
+  return !prop.computed && prop.key.type === "Identifier" && prop.key.name === "async" &&
+    (this.type === types.name || this.type === types.num || this.type === types.string || this.type === types.bracketL || this.type.keyword) &&
+    !lineBreak.test(this.input.slice(this.lastTokEnd, this.start))
+};
+
+// Parse an object literal or binding pattern.
+
+pp$3.parseObj = function(isPattern, refDestructuringErrors) {
+  var this$1 = this;
+
+  var node = this.startNode(), first = true, propHash = {};
+  node.properties = [];
+  this.next();
+  while (!this.eat(types.braceR)) {
+    if (!first) {
+      this$1.expect(types.comma);
+      if (this$1.afterTrailingComma(types.braceR)) { break }
+    } else { first = false; }
+
+    var prop = this$1.parseProperty(isPattern, refDestructuringErrors);
+    this$1.checkPropClash(prop, propHash);
+    node.properties.push(prop);
+  }
+  return this.finishNode(node, isPattern ? "ObjectPattern" : "ObjectExpression")
+};
+
+pp$3.parseProperty = function(isPattern, refDestructuringErrors) {
+  var prop = this.startNode(), isGenerator, isAsync, startPos, startLoc;
+  if (this.options.ecmaVersion >= 6) {
+    prop.method = false;
+    prop.shorthand = false;
+    if (isPattern || refDestructuringErrors) {
+      startPos = this.start;
+      startLoc = this.startLoc;
+    }
+    if (!isPattern)
+      { isGenerator = this.eat(types.star); }
+  }
+  this.parsePropertyName(prop);
+  if (!isPattern && this.options.ecmaVersion >= 8 && !isGenerator && this.isAsyncProp(prop)) {
+    isAsync = true;
+    this.parsePropertyName(prop, refDestructuringErrors);
+  } else {
+    isAsync = false;
+  }
+  this.parsePropertyValue(prop, isPattern, isGenerator, isAsync, startPos, startLoc, refDestructuringErrors);
+  return this.finishNode(prop, "Property")
+};
+
+pp$3.parsePropertyValue = function(prop, isPattern, isGenerator, isAsync, startPos, startLoc, refDestructuringErrors) {
+  if ((isGenerator || isAsync) && this.type === types.colon)
+    { this.unexpected(); }
+
+  if (this.eat(types.colon)) {
+    prop.value = isPattern ? this.parseMaybeDefault(this.start, this.startLoc) : this.parseMaybeAssign(false, refDestructuringErrors);
+    prop.kind = "init";
+  } else if (this.options.ecmaVersion >= 6 && this.type === types.parenL) {
+    if (isPattern) { this.unexpected(); }
+    prop.kind = "init";
+    prop.method = true;
+    prop.value = this.parseMethod(isGenerator, isAsync);
+  } else if (!isPattern &&
+             this.options.ecmaVersion >= 5 && !prop.computed && prop.key.type === "Identifier" &&
+             (prop.key.name === "get" || prop.key.name === "set") &&
+             (this.type != types.comma && this.type != types.braceR)) {
+    if (isGenerator || isAsync) { this.unexpected(); }
+    prop.kind = prop.key.name;
+    this.parsePropertyName(prop);
+    prop.value = this.parseMethod(false);
+    var paramCount = prop.kind === "get" ? 0 : 1;
+    if (prop.value.params.length !== paramCount) {
+      var start = prop.value.start;
+      if (prop.kind === "get")
+        { this.raiseRecoverable(start, "getter should have no params"); }
+      else
+        { this.raiseRecoverable(start, "setter should have exactly one param"); }
+    } else {
+      if (prop.kind === "set" && prop.value.params[0].type === "RestElement")
+        { this.raiseRecoverable(prop.value.params[0].start, "Setter cannot use rest params"); }
+    }
+  } else if (this.options.ecmaVersion >= 6 && !prop.computed && prop.key.type === "Identifier") {
+    this.checkUnreserved(prop.key);
+    prop.kind = "init";
+    if (isPattern) {
+      prop.value = this.parseMaybeDefault(startPos, startLoc, prop.key);
+    } else if (this.type === types.eq && refDestructuringErrors) {
+      if (refDestructuringErrors.shorthandAssign < 0)
+        { refDestructuringErrors.shorthandAssign = this.start; }
+      prop.value = this.parseMaybeDefault(startPos, startLoc, prop.key);
+    } else {
+      prop.value = prop.key;
+    }
+    prop.shorthand = true;
+  } else { this.unexpected(); }
+};
+
+pp$3.parsePropertyName = function(prop) {
+  if (this.options.ecmaVersion >= 6) {
+    if (this.eat(types.bracketL)) {
+      prop.computed = true;
+      prop.key = this.parseMaybeAssign();
+      this.expect(types.bracketR);
+      return prop.key
+    } else {
+      prop.computed = false;
+    }
+  }
+  return prop.key = this.type === types.num || this.type === types.string ? this.parseExprAtom() : this.parseIdent(true)
+};
+
+// Initialize empty function node.
+
+pp$3.initFunction = function(node) {
+  node.id = null;
+  if (this.options.ecmaVersion >= 6) {
+    node.generator = false;
+    node.expression = false;
+  }
+  if (this.options.ecmaVersion >= 8)
+    { node.async = false; }
+};
+
+// Parse object or class method.
+
+pp$3.parseMethod = function(isGenerator, isAsync) {
+  var node = this.startNode(), oldInGen = this.inGenerator, oldInAsync = this.inAsync,
+      oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos, oldInFunc = this.inFunction;
+
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 6)
+    { node.generator = isGenerator; }
+  if (this.options.ecmaVersion >= 8)
+    { node.async = !!isAsync; }
+
+  this.inGenerator = node.generator;
+  this.inAsync = node.async;
+  this.yieldPos = 0;
+  this.awaitPos = 0;
+  this.inFunction = true;
+  this.enterFunctionScope();
+
+  this.expect(types.parenL);
+  node.params = this.parseBindingList(types.parenR, false, this.options.ecmaVersion >= 8);
+  this.checkYieldAwaitInDefaultParams();
+  this.parseFunctionBody(node, false);
+
+  this.inGenerator = oldInGen;
+  this.inAsync = oldInAsync;
+  this.yieldPos = oldYieldPos;
+  this.awaitPos = oldAwaitPos;
+  this.inFunction = oldInFunc;
+  return this.finishNode(node, "FunctionExpression")
+};
+
+// Parse arrow function expression with given parameters.
+
+pp$3.parseArrowExpression = function(node, params, isAsync) {
+  var oldInGen = this.inGenerator, oldInAsync = this.inAsync,
+      oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos, oldInFunc = this.inFunction;
+
+  this.enterFunctionScope();
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 8)
+    { node.async = !!isAsync; }
+
+  this.inGenerator = false;
+  this.inAsync = node.async;
+  this.yieldPos = 0;
+  this.awaitPos = 0;
+  this.inFunction = true;
+
+  node.params = this.toAssignableList(params, true);
+  this.parseFunctionBody(node, true);
+
+  this.inGenerator = oldInGen;
+  this.inAsync = oldInAsync;
+  this.yieldPos = oldYieldPos;
+  this.awaitPos = oldAwaitPos;
+  this.inFunction = oldInFunc;
+  return this.finishNode(node, "ArrowFunctionExpression")
+};
+
+// Parse function body and check parameters.
+
+pp$3.parseFunctionBody = function(node, isArrowFunction) {
+  var isExpression = isArrowFunction && this.type !== types.braceL;
+  var oldStrict = this.strict, useStrict = false;
+
+  if (isExpression) {
+    node.body = this.parseMaybeAssign();
+    node.expression = true;
+    this.checkParams(node, false);
+  } else {
+    var nonSimple = this.options.ecmaVersion >= 7 && !this.isSimpleParamList(node.params);
+    if (!oldStrict || nonSimple) {
+      useStrict = this.strictDirective(this.end);
+      // If this is a strict mode function, verify that argument names
+      // are not repeated, and it does not try to bind the words `eval`
+      // or `arguments`.
+      if (useStrict && nonSimple)
+        { this.raiseRecoverable(node.start, "Illegal 'use strict' directive in function with non-simple parameter list"); }
+    }
+    // Start a new scope with regard to labels and the `inFunction`
+    // flag (restore them to their old value afterwards).
+    var oldLabels = this.labels;
+    this.labels = [];
+    if (useStrict) { this.strict = true; }
+
+    // Add the params to varDeclaredNames to ensure that an error is thrown
+    // if a let/const declaration in the function clashes with one of the params.
+    this.checkParams(node, !oldStrict && !useStrict && !isArrowFunction && this.isSimpleParamList(node.params));
+    node.body = this.parseBlock(false);
+    node.expression = false;
+    this.adaptDirectivePrologue(node.body.body);
+    this.labels = oldLabels;
+  }
+  this.exitFunctionScope();
+
+  if (this.strict && node.id) {
+    // Ensure the function name isn't a forbidden identifier in strict mode, e.g. 'eval'
+    this.checkLVal(node.id, "none");
+  }
+  this.strict = oldStrict;
+};
+
+pp$3.isSimpleParamList = function(params) {
+  for (var i = 0, list = params; i < list.length; i += 1)
+    {
+    var param = list[i];
+
+    if (param.type !== "Identifier") { return false
+  } }
+  return true
+};
+
+// Checks function params for various disallowed patterns such as using "eval"
+// or "arguments" and duplicate parameters.
+
+pp$3.checkParams = function(node, allowDuplicates) {
+  var this$1 = this;
+
+  var nameHash = {};
+  for (var i = 0, list = node.params; i < list.length; i += 1)
+    {
+    var param = list[i];
+
+    this$1.checkLVal(param, "var", allowDuplicates ? null : nameHash);
+  }
+};
+
+// Parses a comma-separated list of expressions, and returns them as
+// an array. `close` is the token type that ends the list, and
+// `allowEmpty` can be turned on to allow subsequent commas with
+// nothing in between them to be parsed as `null` (which is needed
+// for array literals).
+
+pp$3.parseExprList = function(close, allowTrailingComma, allowEmpty, refDestructuringErrors) {
+  var this$1 = this;
+
+  var elts = [], first = true;
+  while (!this.eat(close)) {
+    if (!first) {
+      this$1.expect(types.comma);
+      if (allowTrailingComma && this$1.afterTrailingComma(close)) { break }
+    } else { first = false; }
+
+    var elt = (void 0);
+    if (allowEmpty && this$1.type === types.comma)
+      { elt = null; }
+    else if (this$1.type === types.ellipsis) {
+      elt = this$1.parseSpread(refDestructuringErrors);
+      if (refDestructuringErrors && this$1.type === types.comma && refDestructuringErrors.trailingComma < 0)
+        { refDestructuringErrors.trailingComma = this$1.start; }
+    } else {
+      elt = this$1.parseMaybeAssign(false, refDestructuringErrors);
+    }
+    elts.push(elt);
+  }
+  return elts
+};
+
+pp$3.checkUnreserved = function(ref) {
+  var start = ref.start;
+  var end = ref.end;
+  var name = ref.name;
+
+  if (this.inGenerator && name === "yield")
+    { this.raiseRecoverable(start, "Can not use 'yield' as identifier inside a generator"); }
+  if (this.inAsync && name === "await")
+    { this.raiseRecoverable(start, "Can not use 'await' as identifier inside an async function"); }
+  if (this.isKeyword(name))
+    { this.raise(start, ("Unexpected keyword '" + name + "'")); }
+  if (this.options.ecmaVersion < 6 &&
+    this.input.slice(start, end).indexOf("\\") != -1) { return }
+  var re = this.strict ? this.reservedWordsStrict : this.reservedWords;
+  if (re.test(name))
+    { this.raiseRecoverable(start, ("The keyword '" + name + "' is reserved")); }
+};
+
+// Parse the next token as an identifier. If `liberal` is true (used
+// when parsing properties), it will also convert keywords into
+// identifiers.
+
+pp$3.parseIdent = function(liberal, isBinding) {
+  var node = this.startNode();
+  if (liberal && this.options.allowReserved == "never") { liberal = false; }
+  if (this.type === types.name) {
+    node.name = this.value;
+  } else if (this.type.keyword) {
+    node.name = this.type.keyword;
+
+    // To fix https://github.com/ternjs/acorn/issues/575
+    // `class` and `function` keywords push new context into this.context.
+    // But there is no chance to pop the context if the keyword is consumed as an identifier such as a property name.
+    // If the previous token is a dot, this does not apply because the context-managing code already ignored the keyword
+    if ((node.name === "class" || node.name === "function") &&
+        (this.lastTokEnd !== this.lastTokStart + 1 || this.input.charCodeAt(this.lastTokStart) !== 46)) {
+      this.context.pop();
+    }
+  } else {
+    this.unexpected();
+  }
+  this.next();
+  this.finishNode(node, "Identifier");
+  if (!liberal) { this.checkUnreserved(node); }
+  return node
+};
+
+// Parses yield expression inside generator.
+
+pp$3.parseYield = function() {
+  if (!this.yieldPos) { this.yieldPos = this.start; }
+
+  var node = this.startNode();
+  this.next();
+  if (this.type == types.semi || this.canInsertSemicolon() || (this.type != types.star && !this.type.startsExpr)) {
+    node.delegate = false;
+    node.argument = null;
+  } else {
+    node.delegate = this.eat(types.star);
+    node.argument = this.parseMaybeAssign();
+  }
+  return this.finishNode(node, "YieldExpression")
+};
+
+pp$3.parseAwait = function() {
+  if (!this.awaitPos) { this.awaitPos = this.start; }
+
+  var node = this.startNode();
+  this.next();
+  node.argument = this.parseMaybeUnary(null, true);
+  return this.finishNode(node, "AwaitExpression")
+};
+
+var pp$4 = Parser.prototype;
+
+// This function is used to raise exceptions on parse errors. It
+// takes an offset integer (into the current `input`) to indicate
+// the location of the error, attaches the position to the end
+// of the error message, and then raises a `SyntaxError` with that
+// message.
+
+pp$4.raise = function(pos, message) {
+  var loc = getLineInfo(this.input, pos);
+  message += " (" + loc.line + ":" + loc.column + ")";
+  var err = new SyntaxError(message);
+  err.pos = pos; err.loc = loc; err.raisedAt = this.pos;
+  throw err
+};
+
+pp$4.raiseRecoverable = pp$4.raise;
+
+pp$4.curPosition = function() {
+  if (this.options.locations) {
+    return new Position(this.curLine, this.pos - this.lineStart)
+  }
+};
+
+var pp$5 = Parser.prototype;
+
+// Object.assign polyfill
+var assign = Object.assign || function(target) {
+  var sources = [], len = arguments.length - 1;
+  while ( len-- > 0 ) sources[ len ] = arguments[ len + 1 ];
+
+  for (var i = 0, list = sources; i < list.length; i += 1) {
+    var source = list[i];
+
+    for (var key in source) {
+      if (has(source, key)) {
+        target[key] = source[key];
+      }
+    }
+  }
+  return target
+};
+
+// The functions in this module keep track of declared variables in the current scope in order to detect duplicate variable names.
+
+pp$5.enterFunctionScope = function() {
+  // var: a hash of var-declared names in the current lexical scope
+  // lexical: a hash of lexically-declared names in the current lexical scope
+  // childVar: a hash of var-declared names in all child lexical scopes of the current lexical scope (within the current function scope)
+  // parentLexical: a hash of lexically-declared names in all parent lexical scopes of the current lexical scope (within the current function scope)
+  this.scopeStack.push({var: {}, lexical: {}, childVar: {}, parentLexical: {}});
+};
+
+pp$5.exitFunctionScope = function() {
+  this.scopeStack.pop();
+};
+
+pp$5.enterLexicalScope = function() {
+  var parentScope = this.scopeStack[this.scopeStack.length - 1];
+  var childScope = {var: {}, lexical: {}, childVar: {}, parentLexical: {}};
+
+  this.scopeStack.push(childScope);
+  assign(childScope.parentLexical, parentScope.lexical, parentScope.parentLexical);
+};
+
+pp$5.exitLexicalScope = function() {
+  var childScope = this.scopeStack.pop();
+  var parentScope = this.scopeStack[this.scopeStack.length - 1];
+
+  assign(parentScope.childVar, childScope.var, childScope.childVar);
+};
+
+/**
+ * A name can be declared with `var` if there are no variables with the same name declared with `let`/`const`
+ * in the current lexical scope or any of the parent lexical scopes in this function.
+ */
+pp$5.canDeclareVarName = function(name) {
+  var currentScope = this.scopeStack[this.scopeStack.length - 1];
+
+  return !has(currentScope.lexical, name) && !has(currentScope.parentLexical, name)
+};
+
+/**
+ * A name can be declared with `let`/`const` if there are no variables with the same name declared with `let`/`const`
+ * in the current scope, and there are no variables with the same name declared with `var` in the current scope or in
+ * any child lexical scopes in this function.
+ */
+pp$5.canDeclareLexicalName = function(name) {
+  var currentScope = this.scopeStack[this.scopeStack.length - 1];
+
+  return !has(currentScope.lexical, name) && !has(currentScope.var, name) && !has(currentScope.childVar, name)
+};
+
+pp$5.declareVarName = function(name) {
+  this.scopeStack[this.scopeStack.length - 1].var[name] = true;
+};
+
+pp$5.declareLexicalName = function(name) {
+  this.scopeStack[this.scopeStack.length - 1].lexical[name] = true;
+};
+
+var Node = function Node(parser, pos, loc) {
+  this.type = "";
+  this.start = pos;
+  this.end = 0;
+  if (parser.options.locations)
+    { this.loc = new SourceLocation(parser, loc); }
+  if (parser.options.directSourceFile)
+    { this.sourceFile = parser.options.directSourceFile; }
+  if (parser.options.ranges)
+    { this.range = [pos, 0]; }
+};
+
+// Start an AST node, attaching a start offset.
+
+var pp$6 = Parser.prototype;
+
+pp$6.startNode = function() {
+  return new Node(this, this.start, this.startLoc)
+};
+
+pp$6.startNodeAt = function(pos, loc) {
+  return new Node(this, pos, loc)
+};
+
+// Finish an AST node, adding `type` and `end` properties.
+
+function finishNodeAt(node, type, pos, loc) {
+  node.type = type;
+  node.end = pos;
+  if (this.options.locations)
+    { node.loc.end = loc; }
+  if (this.options.ranges)
+    { node.range[1] = pos; }
+  return node
+}
+
+pp$6.finishNode = function(node, type) {
+  return finishNodeAt.call(this, node, type, this.lastTokEnd, this.lastTokEndLoc)
+};
+
+// Finish node at given position
+
+pp$6.finishNodeAt = function(node, type, pos, loc) {
+  return finishNodeAt.call(this, node, type, pos, loc)
+};
+
+// The algorithm used to determine whether a regexp can appear at a
+// given point in the program is loosely based on sweet.js' approach.
+// See https://github.com/mozilla/sweet.js/wiki/design
+
+var TokContext = function TokContext(token, isExpr, preserveSpace, override, generator) {
+  this.token = token;
+  this.isExpr = !!isExpr;
+  this.preserveSpace = !!preserveSpace;
+  this.override = override;
+  this.generator = !!generator;
+};
+
+var types$1 = {
+  b_stat: new TokContext("{", false),
+  b_expr: new TokContext("{", true),
+  b_tmpl: new TokContext("${", false),
+  p_stat: new TokContext("(", false),
+  p_expr: new TokContext("(", true),
+  q_tmpl: new TokContext("`", true, true, function (p) { return p.tryReadTemplateToken(); }),
+  f_stat: new TokContext("function", false),
+  f_expr: new TokContext("function", true),
+  f_expr_gen: new TokContext("function", true, false, null, true),
+  f_gen: new TokContext("function", false, false, null, true)
+};
+
+var pp$7 = Parser.prototype;
+
+pp$7.initialContext = function() {
+  return [types$1.b_stat]
+};
+
+pp$7.braceIsBlock = function(prevType) {
+  var parent = this.curContext();
+  if (parent === types$1.f_expr || parent === types$1.f_stat)
+    { return true }
+  if (prevType === types.colon && (parent === types$1.b_stat || parent === types$1.b_expr))
+    { return !parent.isExpr }
+
+  // The check for `tt.name && exprAllowed` detects whether we are
+  // after a `yield` or `of` construct. See the `updateContext` for
+  // `tt.name`.
+  if (prevType === types._return || prevType == types.name && this.exprAllowed)
+    { return lineBreak.test(this.input.slice(this.lastTokEnd, this.start)) }
+  if (prevType === types._else || prevType === types.semi || prevType === types.eof || prevType === types.parenR || prevType == types.arrow)
+    { return true }
+  if (prevType == types.braceL)
+    { return parent === types$1.b_stat }
+  if (prevType == types._var || prevType == types.name)
+    { return false }
+  return !this.exprAllowed
+};
+
+pp$7.inGeneratorContext = function() {
+  var this$1 = this;
+
+  for (var i = this.context.length - 1; i >= 1; i--) {
+    var context = this$1.context[i];
+    if (context.token === "function")
+      { return context.generator }
+  }
+  return false
+};
+
+pp$7.updateContext = function(prevType) {
+  var update, type = this.type;
+  if (type.keyword && prevType == types.dot)
+    { this.exprAllowed = false; }
+  else if (update = type.updateContext)
+    { update.call(this, prevType); }
+  else
+    { this.exprAllowed = type.beforeExpr; }
+};
+
+// Token-specific context update code
+
+types.parenR.updateContext = types.braceR.updateContext = function() {
+  if (this.context.length == 1) {
+    this.exprAllowed = true;
+    return
+  }
+  var out = this.context.pop();
+  if (out === types$1.b_stat && this.curContext().token === "function") {
+    out = this.context.pop();
+  }
+  this.exprAllowed = !out.isExpr;
+};
+
+types.braceL.updateContext = function(prevType) {
+  this.context.push(this.braceIsBlock(prevType) ? types$1.b_stat : types$1.b_expr);
+  this.exprAllowed = true;
+};
+
+types.dollarBraceL.updateContext = function() {
+  this.context.push(types$1.b_tmpl);
+  this.exprAllowed = true;
+};
+
+types.parenL.updateContext = function(prevType) {
+  var statementParens = prevType === types._if || prevType === types._for || prevType === types._with || prevType === types._while;
+  this.context.push(statementParens ? types$1.p_stat : types$1.p_expr);
+  this.exprAllowed = true;
+};
+
+types.incDec.updateContext = function() {
+  // tokExprAllowed stays unchanged
+};
+
+types._function.updateContext = types._class.updateContext = function(prevType) {
+  if (prevType.beforeExpr && prevType !== types.semi && prevType !== types._else &&
+      !((prevType === types.colon || prevType === types.braceL) && this.curContext() === types$1.b_stat))
+    { this.context.push(types$1.f_expr); }
+  else
+    { this.context.push(types$1.f_stat); }
+  this.exprAllowed = false;
+};
+
+types.backQuote.updateContext = function() {
+  if (this.curContext() === types$1.q_tmpl)
+    { this.context.pop(); }
+  else
+    { this.context.push(types$1.q_tmpl); }
+  this.exprAllowed = false;
+};
+
+types.star.updateContext = function(prevType) {
+  if (prevType == types._function) {
+    var index = this.context.length - 1;
+    if (this.context[index] === types$1.f_expr)
+      { this.context[index] = types$1.f_expr_gen; }
+    else
+      { this.context[index] = types$1.f_gen; }
+  }
+  this.exprAllowed = true;
+};
+
+types.name.updateContext = function(prevType) {
+  var allowed = false;
+  if (this.options.ecmaVersion >= 6) {
+    if (this.value == "of" && !this.exprAllowed ||
+        this.value == "yield" && this.inGeneratorContext())
+      { allowed = true; }
+  }
+  this.exprAllowed = allowed;
+};
+
+// Object type used to represent tokens. Note that normally, tokens
+// simply exist as properties on the parser object. This is only
+// used for the onToken callback and the external tokenizer.
+
+var Token = function Token(p) {
+  this.type = p.type;
+  this.value = p.value;
+  this.start = p.start;
+  this.end = p.end;
+  if (p.options.locations)
+    { this.loc = new SourceLocation(p, p.startLoc, p.endLoc); }
+  if (p.options.ranges)
+    { this.range = [p.start, p.end]; }
+};
+
+// ## Tokenizer
+
+var pp$8 = Parser.prototype;
+
+// Are we running under Rhino?
+var isRhino = typeof Packages == "object" && Object.prototype.toString.call(Packages) == "[object JavaPackage]";
+
+// Move to the next token
+
+pp$8.next = function() {
+  if (this.options.onToken)
+    { this.options.onToken(new Token(this)); }
+
+  this.lastTokEnd = this.end;
+  this.lastTokStart = this.start;
+  this.lastTokEndLoc = this.endLoc;
+  this.lastTokStartLoc = this.startLoc;
+  this.nextToken();
+};
+
+pp$8.getToken = function() {
+  this.next();
+  return new Token(this)
+};
+
+// If we're in an ES6 environment, make parsers iterable
+if (typeof Symbol !== "undefined")
+  { pp$8[Symbol.iterator] = function() {
+    var this$1 = this;
+
+    return {
+      next: function () {
+        var token = this$1.getToken();
+        return {
+          done: token.type === types.eof,
+          value: token
+        }
+      }
+    }
+  }; }
+
+// Toggle strict mode. Re-reads the next number or string to please
+// pedantic tests (`"use strict"; 010;` should fail).
+
+pp$8.curContext = function() {
+  return this.context[this.context.length - 1]
+};
+
+// Read a single token, updating the parser object's token-related
+// properties.
+
+pp$8.nextToken = function() {
+  var curContext = this.curContext();
+  if (!curContext || !curContext.preserveSpace) { this.skipSpace(); }
+
+  this.start = this.pos;
+  if (this.options.locations) { this.startLoc = this.curPosition(); }
+  if (this.pos >= this.input.length) { return this.finishToken(types.eof) }
+
+  if (curContext.override) { return curContext.override(this) }
+  else { this.readToken(this.fullCharCodeAtPos()); }
+};
+
+pp$8.readToken = function(code) {
+  // Identifier or keyword. '\uXXXX' sequences are allowed in
+  // identifiers, so '\' also dispatches to that.
+  if (isIdentifierStart(code, this.options.ecmaVersion >= 6) || code === 92 /* '\' */)
+    { return this.readWord() }
+
+  return this.getTokenFromCode(code)
+};
+
+pp$8.fullCharCodeAtPos = function() {
+  var code = this.input.charCodeAt(this.pos);
+  if (code <= 0xd7ff || code >= 0xe000) { return code }
+  var next = this.input.charCodeAt(this.pos + 1);
+  return (code << 10) + next - 0x35fdc00
+};
+
+pp$8.skipBlockComment = function() {
+  var this$1 = this;
+
+  var startLoc = this.options.onComment && this.curPosition();
+  var start = this.pos, end = this.input.indexOf("*/", this.pos += 2);
+  if (end === -1) { this.raise(this.pos - 2, "Unterminated comment"); }
+  this.pos = end + 2;
+  if (this.options.locations) {
+    lineBreakG.lastIndex = start;
+    var match;
+    while ((match = lineBreakG.exec(this.input)) && match.index < this.pos) {
+      ++this$1.curLine;
+      this$1.lineStart = match.index + match[0].length;
+    }
+  }
+  if (this.options.onComment)
+    { this.options.onComment(true, this.input.slice(start + 2, end), start, this.pos,
+                           startLoc, this.curPosition()); }
+};
+
+pp$8.skipLineComment = function(startSkip) {
+  var this$1 = this;
+
+  var start = this.pos;
+  var startLoc = this.options.onComment && this.curPosition();
+  var ch = this.input.charCodeAt(this.pos += startSkip);
+  while (this.pos < this.input.length && !isNewLine(ch)) {
+    ch = this$1.input.charCodeAt(++this$1.pos);
+  }
+  if (this.options.onComment)
+    { this.options.onComment(false, this.input.slice(start + startSkip, this.pos), start, this.pos,
+                           startLoc, this.curPosition()); }
+};
+
+// Called at the start of the parse and after every token. Skips
+// whitespace and comments, and.
+
+pp$8.skipSpace = function() {
+  var this$1 = this;
+
+  loop: while (this.pos < this.input.length) {
+    var ch = this$1.input.charCodeAt(this$1.pos);
+    switch (ch) {
+    case 32: case 160: // ' '
+      ++this$1.pos;
+      break
+    case 13:
+      if (this$1.input.charCodeAt(this$1.pos + 1) === 10) {
+        ++this$1.pos;
+      }
+    case 10: case 8232: case 8233:
+      ++this$1.pos;
+      if (this$1.options.locations) {
+        ++this$1.curLine;
+        this$1.lineStart = this$1.pos;
+      }
+      break
+    case 47: // '/'
+      switch (this$1.input.charCodeAt(this$1.pos + 1)) {
+      case 42: // '*'
+        this$1.skipBlockComment();
+        break
+      case 47:
+        this$1.skipLineComment(2);
+        break
+      default:
+        break loop
+      }
+      break
+    default:
+      if (ch > 8 && ch < 14 || ch >= 5760 && nonASCIIwhitespace.test(String.fromCharCode(ch))) {
+        ++this$1.pos;
+      } else {
+        break loop
+      }
+    }
+  }
+};
+
+// Called at the end of every token. Sets `end`, `val`, and
+// maintains `context` and `exprAllowed`, and skips the space after
+// the token, so that the next one's `start` will point at the
+// right position.
+
+pp$8.finishToken = function(type, val) {
+  this.end = this.pos;
+  if (this.options.locations) { this.endLoc = this.curPosition(); }
+  var prevType = this.type;
+  this.type = type;
+  this.value = val;
+
+  this.updateContext(prevType);
+};
+
+// ### Token reading
+
+// This is the function that is called to fetch the next token. It
+// is somewhat obscure, because it works in character codes rather
+// than characters, and because operator parsing has been inlined
+// into it.
+//
+// All in the name of speed.
+//
+pp$8.readToken_dot = function() {
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next >= 48 && next <= 57) { return this.readNumber(true) }
+  var next2 = this.input.charCodeAt(this.pos + 2);
+  if (this.options.ecmaVersion >= 6 && next === 46 && next2 === 46) { // 46 = dot '.'
+    this.pos += 3;
+    return this.finishToken(types.ellipsis)
+  } else {
+    ++this.pos;
+    return this.finishToken(types.dot)
+  }
+};
+
+pp$8.readToken_slash = function() { // '/'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (this.exprAllowed) { ++this.pos; return this.readRegexp() }
+  if (next === 61) { return this.finishOp(types.assign, 2) }
+  return this.finishOp(types.slash, 1)
+};
+
+pp$8.readToken_mult_modulo_exp = function(code) { // '%*'
+  var next = this.input.charCodeAt(this.pos + 1);
+  var size = 1;
+  var tokentype = code === 42 ? types.star : types.modulo;
+
+  // exponentiation operator ** and **=
+  if (this.options.ecmaVersion >= 7 && code == 42 && next === 42) {
+    ++size;
+    tokentype = types.starstar;
+    next = this.input.charCodeAt(this.pos + 2);
+  }
+
+  if (next === 61) { return this.finishOp(types.assign, size + 1) }
+  return this.finishOp(tokentype, size)
+};
+
+pp$8.readToken_pipe_amp = function(code) { // '|&'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === code) { return this.finishOp(code === 124 ? types.logicalOR : types.logicalAND, 2) }
+  if (next === 61) { return this.finishOp(types.assign, 2) }
+  return this.finishOp(code === 124 ? types.bitwiseOR : types.bitwiseAND, 1)
+};
+
+pp$8.readToken_caret = function() { // '^'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === 61) { return this.finishOp(types.assign, 2) }
+  return this.finishOp(types.bitwiseXOR, 1)
+};
+
+pp$8.readToken_plus_min = function(code) { // '+-'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === code) {
+    if (next == 45 && !this.inModule && this.input.charCodeAt(this.pos + 2) == 62 &&
+        (this.lastTokEnd === 0 || lineBreak.test(this.input.slice(this.lastTokEnd, this.pos)))) {
+      // A `-->` line comment
+      this.skipLineComment(3);
+      this.skipSpace();
+      return this.nextToken()
+    }
+    return this.finishOp(types.incDec, 2)
+  }
+  if (next === 61) { return this.finishOp(types.assign, 2) }
+  return this.finishOp(types.plusMin, 1)
+};
+
+pp$8.readToken_lt_gt = function(code) { // '<>'
+  var next = this.input.charCodeAt(this.pos + 1);
+  var size = 1;
+  if (next === code) {
+    size = code === 62 && this.input.charCodeAt(this.pos + 2) === 62 ? 3 : 2;
+    if (this.input.charCodeAt(this.pos + size) === 61) { return this.finishOp(types.assign, size + 1) }
+    return this.finishOp(types.bitShift, size)
+  }
+  if (next == 33 && code == 60 && !this.inModule && this.input.charCodeAt(this.pos + 2) == 45 &&
+      this.input.charCodeAt(this.pos + 3) == 45) {
+    // `<!--`, an XML-style comment that should be interpreted as a line comment
+    this.skipLineComment(4);
+    this.skipSpace();
+    return this.nextToken()
+  }
+  if (next === 61) { size = 2; }
+  return this.finishOp(types.relational, size)
+};
+
+pp$8.readToken_eq_excl = function(code) { // '=!'
+  var next = this.input.charCodeAt(this.pos + 1);
+  if (next === 61) { return this.finishOp(types.equality, this.input.charCodeAt(this.pos + 2) === 61 ? 3 : 2) }
+  if (code === 61 && next === 62 && this.options.ecmaVersion >= 6) { // '=>'
+    this.pos += 2;
+    return this.finishToken(types.arrow)
+  }
+  return this.finishOp(code === 61 ? types.eq : types.prefix, 1)
+};
+
+pp$8.getTokenFromCode = function(code) {
+  switch (code) {
+    // The interpretation of a dot depends on whether it is followed
+    // by a digit or another two dots.
+  case 46: // '.'
+    return this.readToken_dot()
+
+    // Punctuation tokens.
+  case 40: ++this.pos; return this.finishToken(types.parenL)
+  case 41: ++this.pos; return this.finishToken(types.parenR)
+  case 59: ++this.pos; return this.finishToken(types.semi)
+  case 44: ++this.pos; return this.finishToken(types.comma)
+  case 91: ++this.pos; return this.finishToken(types.bracketL)
+  case 93: ++this.pos; return this.finishToken(types.bracketR)
+  case 123: ++this.pos; return this.finishToken(types.braceL)
+  case 125: ++this.pos; return this.finishToken(types.braceR)
+  case 58: ++this.pos; return this.finishToken(types.colon)
+  case 63: ++this.pos; return this.finishToken(types.question)
+
+  case 96: // '`'
+    if (this.options.ecmaVersion < 6) { break }
+    ++this.pos;
+    return this.finishToken(types.backQuote)
+
+  case 48: // '0'
+    var next = this.input.charCodeAt(this.pos + 1);
+    if (next === 120 || next === 88) { return this.readRadixNumber(16) } // '0x', '0X' - hex number
+    if (this.options.ecmaVersion >= 6) {
+      if (next === 111 || next === 79) { return this.readRadixNumber(8) } // '0o', '0O' - octal number
+      if (next === 98 || next === 66) { return this.readRadixNumber(2) } // '0b', '0B' - binary number
+    }
+    // Anything else beginning with a digit is an integer, octal
+    // number, or float.
+  case 49: case 50: case 51: case 52: case 53: case 54: case 55: case 56: case 57: // 1-9
+    return this.readNumber(false)
+
+    // Quotes produce strings.
+  case 34: case 39: // '"', "'"
+    return this.readString(code)
+
+    // Operators are parsed inline in tiny state machines. '=' (61) is
+    // often referred to. `finishOp` simply skips the amount of
+    // characters it is given as second argument, and returns a token
+    // of the type given by its first argument.
+
+  case 47: // '/'
+    return this.readToken_slash()
+
+  case 37: case 42: // '%*'
+    return this.readToken_mult_modulo_exp(code)
+
+  case 124: case 38: // '|&'
+    return this.readToken_pipe_amp(code)
+
+  case 94: // '^'
+    return this.readToken_caret()
+
+  case 43: case 45: // '+-'
+    return this.readToken_plus_min(code)
+
+  case 60: case 62: // '<>'
+    return this.readToken_lt_gt(code)
+
+  case 61: case 33: // '=!'
+    return this.readToken_eq_excl(code)
+
+  case 126: // '~'
+    return this.finishOp(types.prefix, 1)
+  }
+
+  this.raise(this.pos, "Unexpected character '" + codePointToString(code) + "'");
+};
+
+pp$8.finishOp = function(type, size) {
+  var str = this.input.slice(this.pos, this.pos + size);
+  this.pos += size;
+  return this.finishToken(type, str)
+};
+
+// Parse a regular expression. Some context-awareness is necessary,
+// since a '/' inside a '[]' set does not end the expression.
+
+function tryCreateRegexp(src, flags, throwErrorAt, parser) {
+  try {
+    return new RegExp(src, flags)
+  } catch (e) {
+    if (throwErrorAt !== undefined) {
+      if (e instanceof SyntaxError) { parser.raise(throwErrorAt, "Error parsing regular expression: " + e.message); }
+      throw e
+    }
+  }
+}
+
+var regexpUnicodeSupport = !!tryCreateRegexp("\uffff", "u");
+
+pp$8.readRegexp = function() {
+  var this$1 = this;
+
+  var escaped, inClass, start = this.pos;
+  for (;;) {
+    if (this$1.pos >= this$1.input.length) { this$1.raise(start, "Unterminated regular expression"); }
+    var ch = this$1.input.charAt(this$1.pos);
+    if (lineBreak.test(ch)) { this$1.raise(start, "Unterminated regular expression"); }
+    if (!escaped) {
+      if (ch === "[") { inClass = true; }
+      else if (ch === "]" && inClass) { inClass = false; }
+      else if (ch === "/" && !inClass) { break }
+      escaped = ch === "\\";
+    } else { escaped = false; }
+    ++this$1.pos;
+  }
+  var content = this.input.slice(start, this.pos);
+  ++this.pos;
+  // Need to use `readWord1` because '\uXXXX' sequences are allowed
+  // here (don't ask).
+  var mods = this.readWord1();
+  var tmp = content, tmpFlags = "";
+  if (mods) {
+    var validFlags = /^[gim]*$/;
+    if (this.options.ecmaVersion >= 6) { validFlags = /^[gimuy]*$/; }
+    if (!validFlags.test(mods)) { this.raise(start, "Invalid regular expression flag"); }
+    if (mods.indexOf("u") >= 0) {
+      if (regexpUnicodeSupport) {
+        tmpFlags = "u";
+      } else {
+        // Replace each astral symbol and every Unicode escape sequence that
+        // possibly represents an astral symbol or a paired surrogate with a
+        // single ASCII symbol to avoid throwing on regular expressions that
+        // are only valid in combination with the `/u` flag.
+        // Note: replacing with the ASCII symbol `x` might cause false
+        // negatives in unlikely scenarios. For example, `[\u{61}-b]` is a
+        // perfectly valid pattern that is equivalent to `[a-b]`, but it would
+        // be replaced by `[x-b]` which throws an error.
+        tmp = tmp.replace(/\\u\{([0-9a-fA-F]+)\}/g, function (_match, code, offset) {
+          code = Number("0x" + code);
+          if (code > 0x10FFFF) { this$1.raise(start + offset + 3, "Code point out of bounds"); }
+          return "x"
+        });
+        tmp = tmp.replace(/\\u([a-fA-F0-9]{4})|[\uD800-\uDBFF][\uDC00-\uDFFF]/g, "x");
+        tmpFlags = tmpFlags.replace("u", "");
+      }
+    }
+  }
+  // Detect invalid regular expressions.
+  var value = null;
+  // Rhino's regular expression parser is flaky and throws uncatchable exceptions,
+  // so don't do detection if we are running under Rhino
+  if (!isRhino) {
+    tryCreateRegexp(tmp, tmpFlags, start, this);
+    // Get a regular expression object for this pattern-flag pair, or `null` in
+    // case the current environment doesn't support the flags it uses.
+    value = tryCreateRegexp(content, mods);
+  }
+  return this.finishToken(types.regexp, {pattern: content, flags: mods, value: value})
+};
+
+// Read an integer in the given radix. Return null if zero digits
+// were read, the integer value otherwise. When `len` is given, this
+// will return `null` unless the integer has exactly `len` digits.
+
+pp$8.readInt = function(radix, len) {
+  var this$1 = this;
+
+  var start = this.pos, total = 0;
+  for (var i = 0, e = len == null ? Infinity : len; i < e; ++i) {
+    var code = this$1.input.charCodeAt(this$1.pos), val = (void 0);
+    if (code >= 97) { val = code - 97 + 10; } // a
+    else if (code >= 65) { val = code - 65 + 10; } // A
+    else if (code >= 48 && code <= 57) { val = code - 48; } // 0-9
+    else { val = Infinity; }
+    if (val >= radix) { break }
+    ++this$1.pos;
+    total = total * radix + val;
+  }
+  if (this.pos === start || len != null && this.pos - start !== len) { return null }
+
+  return total
+};
+
+pp$8.readRadixNumber = function(radix) {
+  this.pos += 2; // 0x
+  var val = this.readInt(radix);
+  if (val == null) { this.raise(this.start + 2, "Expected number in radix " + radix); }
+  if (isIdentifierStart(this.fullCharCodeAtPos())) { this.raise(this.pos, "Identifier directly after number"); }
+  return this.finishToken(types.num, val)
+};
+
+// Read an integer, octal integer, or floating-point number.
+
+pp$8.readNumber = function(startsWithDot) {
+  var start = this.pos, isFloat = false, octal = this.input.charCodeAt(this.pos) === 48;
+  if (!startsWithDot && this.readInt(10) === null) { this.raise(start, "Invalid number"); }
+  if (octal && this.pos == start + 1) { octal = false; }
+  var next = this.input.charCodeAt(this.pos);
+  if (next === 46 && !octal) { // '.'
+    ++this.pos;
+    this.readInt(10);
+    isFloat = true;
+    next = this.input.charCodeAt(this.pos);
+  }
+  if ((next === 69 || next === 101) && !octal) { // 'eE'
+    next = this.input.charCodeAt(++this.pos);
+    if (next === 43 || next === 45) { ++this.pos; } // '+-'
+    if (this.readInt(10) === null) { this.raise(start, "Invalid number"); }
+    isFloat = true;
+  }
+  if (isIdentifierStart(this.fullCharCodeAtPos())) { this.raise(this.pos, "Identifier directly after number"); }
+
+  var str = this.input.slice(start, this.pos), val;
+  if (isFloat) { val = parseFloat(str); }
+  else if (!octal || str.length === 1) { val = parseInt(str, 10); }
+  else if (this.strict) { this.raise(start, "Invalid number"); }
+  else if (/[89]/.test(str)) { val = parseInt(str, 10); }
+  else { val = parseInt(str, 8); }
+  return this.finishToken(types.num, val)
+};
+
+// Read a string value, interpreting backslash-escapes.
+
+pp$8.readCodePoint = function() {
+  var ch = this.input.charCodeAt(this.pos), code;
+
+  if (ch === 123) { // '{'
+    if (this.options.ecmaVersion < 6) { this.unexpected(); }
+    var codePos = ++this.pos;
+    code = this.readHexChar(this.input.indexOf("}", this.pos) - this.pos);
+    ++this.pos;
+    if (code > 0x10FFFF) { this.invalidStringToken(codePos, "Code point out of bounds"); }
+  } else {
+    code = this.readHexChar(4);
+  }
+  return code
+};
+
+function codePointToString(code) {
+  // UTF-16 Decoding
+  if (code <= 0xFFFF) { return String.fromCharCode(code) }
+  code -= 0x10000;
+  return String.fromCharCode((code >> 10) + 0xD800, (code & 1023) + 0xDC00)
+}
+
+pp$8.readString = function(quote) {
+  var this$1 = this;
+
+  var out = "", chunkStart = ++this.pos;
+  for (;;) {
+    if (this$1.pos >= this$1.input.length) { this$1.raise(this$1.start, "Unterminated string constant"); }
+    var ch = this$1.input.charCodeAt(this$1.pos);
+    if (ch === quote) { break }
+    if (ch === 92) { // '\'
+      out += this$1.input.slice(chunkStart, this$1.pos);
+      out += this$1.readEscapedChar(false);
+      chunkStart = this$1.pos;
+    } else {
+      if (isNewLine(ch)) { this$1.raise(this$1.start, "Unterminated string constant"); }
+      ++this$1.pos;
+    }
+  }
+  out += this.input.slice(chunkStart, this.pos++);
+  return this.finishToken(types.string, out)
+};
+
+// Reads template string tokens.
+
+var INVALID_TEMPLATE_ESCAPE_ERROR = {};
+
+pp$8.tryReadTemplateToken = function() {
+  this.inTemplateElement = true;
+  try {
+    this.readTmplToken();
+  } catch (err) {
+    if (err === INVALID_TEMPLATE_ESCAPE_ERROR) {
+      this.readInvalidTemplateToken();
+    } else {
+      throw err
+    }
+  }
+
+  this.inTemplateElement = false;
+};
+
+pp$8.invalidStringToken = function(position, message) {
+  if (this.inTemplateElement && this.options.ecmaVersion >= 9) {
+    throw INVALID_TEMPLATE_ESCAPE_ERROR
+  } else {
+    this.raise(position, message);
+  }
+};
+
+pp$8.readTmplToken = function() {
+  var this$1 = this;
+
+  var out = "", chunkStart = this.pos;
+  for (;;) {
+    if (this$1.pos >= this$1.input.length) { this$1.raise(this$1.start, "Unterminated template"); }
+    var ch = this$1.input.charCodeAt(this$1.pos);
+    if (ch === 96 || ch === 36 && this$1.input.charCodeAt(this$1.pos + 1) === 123) { // '`', '${'
+      if (this$1.pos === this$1.start && (this$1.type === types.template || this$1.type === types.invalidTemplate)) {
+        if (ch === 36) {
+          this$1.pos += 2;
+          return this$1.finishToken(types.dollarBraceL)
+        } else {
+          ++this$1.pos;
+          return this$1.finishToken(types.backQuote)
+        }
+      }
+      out += this$1.input.slice(chunkStart, this$1.pos);
+      return this$1.finishToken(types.template, out)
+    }
+    if (ch === 92) { // '\'
+      out += this$1.input.slice(chunkStart, this$1.pos);
+      out += this$1.readEscapedChar(true);
+      chunkStart = this$1.pos;
+    } else if (isNewLine(ch)) {
+      out += this$1.input.slice(chunkStart, this$1.pos);
+      ++this$1.pos;
+      switch (ch) {
+      case 13:
+        if (this$1.input.charCodeAt(this$1.pos) === 10) { ++this$1.pos; }
+      case 10:
+        out += "\n";
+        break
+      default:
+        out += String.fromCharCode(ch);
+        break
+      }
+      if (this$1.options.locations) {
+        ++this$1.curLine;
+        this$1.lineStart = this$1.pos;
+      }
+      chunkStart = this$1.pos;
+    } else {
+      ++this$1.pos;
+    }
+  }
+};
+
+// Reads a template token to search for the end, without validating any escape sequences
+pp$8.readInvalidTemplateToken = function() {
+  var this$1 = this;
+
+  for (; this.pos < this.input.length; this.pos++) {
+    switch (this$1.input[this$1.pos]) {
+    case "\\":
+      ++this$1.pos;
+      break
+
+    case "$":
+      if (this$1.input[this$1.pos + 1] !== "{") {
+        break
+      }
+    // falls through
+
+    case "`":
+      return this$1.finishToken(types.invalidTemplate, this$1.input.slice(this$1.start, this$1.pos))
+
+    // no default
+    }
+  }
+  this.raise(this.start, "Unterminated template");
+};
+
+// Used to read escaped characters
+
+pp$8.readEscapedChar = function(inTemplate) {
+  var ch = this.input.charCodeAt(++this.pos);
+  ++this.pos;
+  switch (ch) {
+  case 110: return "\n" // 'n' -> '\n'
+  case 114: return "\r" // 'r' -> '\r'
+  case 120: return String.fromCharCode(this.readHexChar(2)) // 'x'
+  case 117: return codePointToString(this.readCodePoint()) // 'u'
+  case 116: return "\t" // 't' -> '\t'
+  case 98: return "\b" // 'b' -> '\b'
+  case 118: return "\u000b" // 'v' -> '\u000b'
+  case 102: return "\f" // 'f' -> '\f'
+  case 13: if (this.input.charCodeAt(this.pos) === 10) { ++this.pos; } // '\r\n'
+  case 10: // ' \n'
+    if (this.options.locations) { this.lineStart = this.pos; ++this.curLine; }
+    return ""
+  default:
+    if (ch >= 48 && ch <= 55) {
+      var octalStr = this.input.substr(this.pos - 1, 3).match(/^[0-7]+/)[0];
+      var octal = parseInt(octalStr, 8);
+      if (octal > 255) {
+        octalStr = octalStr.slice(0, -1);
+        octal = parseInt(octalStr, 8);
+      }
+      if (octalStr !== "0" && (this.strict || inTemplate)) {
+        this.invalidStringToken(this.pos - 2, "Octal literal in strict mode");
+      }
+      this.pos += octalStr.length - 1;
+      return String.fromCharCode(octal)
+    }
+    return String.fromCharCode(ch)
+  }
+};
+
+// Used to read character escape sequences ('\x', '\u', '\U').
+
+pp$8.readHexChar = function(len) {
+  var codePos = this.pos;
+  var n = this.readInt(16, len);
+  if (n === null) { this.invalidStringToken(codePos, "Bad character escape sequence"); }
+  return n
+};
+
+// Read an identifier, and return it as a string. Sets `this.containsEsc`
+// to whether the word contained a '\u' escape.
+//
+// Incrementally adds only escaped chars, adding other chunks as-is
+// as a micro-optimization.
+
+pp$8.readWord1 = function() {
+  var this$1 = this;
+
+  this.containsEsc = false;
+  var word = "", first = true, chunkStart = this.pos;
+  var astral = this.options.ecmaVersion >= 6;
+  while (this.pos < this.input.length) {
+    var ch = this$1.fullCharCodeAtPos();
+    if (isIdentifierChar(ch, astral)) {
+      this$1.pos += ch <= 0xffff ? 1 : 2;
+    } else if (ch === 92) { // "\"
+      this$1.containsEsc = true;
+      word += this$1.input.slice(chunkStart, this$1.pos);
+      var escStart = this$1.pos;
+      if (this$1.input.charCodeAt(++this$1.pos) != 117) // "u"
+        { this$1.invalidStringToken(this$1.pos, "Expecting Unicode escape sequence \\uXXXX"); }
+      ++this$1.pos;
+      var esc = this$1.readCodePoint();
+      if (!(first ? isIdentifierStart : isIdentifierChar)(esc, astral))
+        { this$1.invalidStringToken(escStart, "Invalid Unicode escape"); }
+      word += codePointToString(esc);
+      chunkStart = this$1.pos;
+    } else {
+      break
+    }
+    first = false;
+  }
+  return word + this.input.slice(chunkStart, this.pos)
+};
+
+// Read an identifier or keyword token. Will check for reserved
+// words when necessary.
+
+pp$8.readWord = function() {
+  var word = this.readWord1();
+  var type = types.name;
+  if (this.keywords.test(word)) {
+    if (this.containsEsc) { this.raiseRecoverable(this.start, "Escape sequence in keyword " + word); }
+    type = keywords$1[word];
+  }
+  return this.finishToken(type, word)
+};
+
+// Acorn is a tiny, fast JavaScript parser written in JavaScript.
+//
+// Acorn was written by Marijn Haverbeke, Ingvar Stepanyan, and
+// various contributors and released under an MIT license.
+//
+// Git repositories for Acorn are available at
+//
+//     http://marijnhaverbeke.nl/git/acorn
+//     https://github.com/ternjs/acorn.git
+//
+// Please use the [github bug tracker][ghbt] to report issues.
+//
+// [ghbt]: https://github.com/ternjs/acorn/issues
+//
+// This file defines the main parser interface. The library also comes
+// with a [error-tolerant parser][dammit] and an
+// [abstract syntax tree walker][walk], defined in other files.
+//
+// [dammit]: acorn_loose.js
+// [walk]: util/walk.js
+
+var version = "5.2.1";
+
+// The main exported interface (under `self.acorn` when in the
+// browser) is a `parse` function that takes a code string and
+// returns an abstract syntax tree as specified by [Mozilla parser
+// API][api].
+//
+// [api]: https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API
+
+function parse(input, options) {
+  return new Parser(options, input).parse()
+}
+
+// This function tries to parse a single expression at a given
+// offset in a string. Useful for parsing mixed-language formats
+// that embed JavaScript expressions.
+
+function parseExpressionAt(input, pos, options) {
+  var p = new Parser(options, input, pos);
+  p.nextToken();
+  return p.parseExpression()
+}
+
+// Acorn is organized as a tokenizer and a recursive-descent parser.
+// The `tokenizer` export provides an interface to the tokenizer.
+
+function tokenizer(input, options) {
+  return new Parser(options, input)
+}
+
+// This is a terrible kludge to support the existing, pre-ES6
+// interface where the loose parser module retroactively adds exports
+// to this module.
+ // eslint-disable-line camelcase
+function addLooseExports(parse, Parser$$1, plugins$$1) {
+  exports.parse_dammit = parse; // eslint-disable-line camelcase
+  exports.LooseParser = Parser$$1;
+  exports.pluginsLoose = plugins$$1;
+}
+
+exports.version = version;
+exports.parse = parse;
+exports.parseExpressionAt = parseExpressionAt;
+exports.tokenizer = tokenizer;
+exports.addLooseExports = addLooseExports;
+exports.Parser = Parser;
+exports.plugins = plugins;
+exports.defaultOptions = defaultOptions;
+exports.Position = Position;
+exports.SourceLocation = SourceLocation;
+exports.getLineInfo = getLineInfo;
+exports.Node = Node;
+exports.TokenType = TokenType;
+exports.tokTypes = types;
+exports.keywordTypes = keywords$1;
+exports.TokContext = TokContext;
+exports.tokContexts = types$1;
+exports.isIdentifierChar = isIdentifierChar;
+exports.isIdentifierStart = isIdentifierStart;
+exports.Token = Token;
+exports.isNewLine = isNewLine;
+exports.lineBreak = lineBreak;
+exports.lineBreakG = lineBreakG;
+exports.nonASCIIwhitespace = nonASCIIwhitespace;
+
+Object.defineProperty(exports, '__esModule', { value: true });
+
+})));
diff --git a/deps/acorn/dist/acorn_loose.es.js b/deps/acorn/dist/acorn_loose.es.js
new file mode 100644
index 0000000000..469f73a2ff
--- /dev/null
+++ b/deps/acorn/dist/acorn_loose.es.js
@@ -0,0 +1,1390 @@
+import { Node, SourceLocation, Token, addLooseExports, defaultOptions, getLineInfo, isNewLine, lineBreak, lineBreakG, tokTypes, tokenizer } from './acorn.es';
+
+// Registered plugins
+var pluginsLoose = {};
+
+var LooseParser = function LooseParser(input, options) {
+  if ( options === void 0 ) options = {};
+
+  this.toks = tokenizer(input, options);
+  this.options = this.toks.options;
+  this.input = this.toks.input;
+  this.tok = this.last = {type: tokTypes.eof, start: 0, end: 0};
+  if (this.options.locations) {
+    var here = this.toks.curPosition();
+    this.tok.loc = new SourceLocation(this.toks, here, here);
+  }
+  this.ahead = []; // Tokens ahead
+  this.context = []; // Indentation contexted
+  this.curIndent = 0;
+  this.curLineStart = 0;
+  this.nextLineStart = this.lineEnd(this.curLineStart) + 1;
+  this.inAsync = false;
+  // Load plugins
+  this.options.pluginsLoose = options.pluginsLoose || {};
+  this.loadPlugins(this.options.pluginsLoose);
+};
+
+LooseParser.prototype.startNode = function startNode () {
+  return new Node(this.toks, this.tok.start, this.options.locations ? this.tok.loc.start : null)
+};
+
+LooseParser.prototype.storeCurrentPos = function storeCurrentPos () {
+  return this.options.locations ? [this.tok.start, this.tok.loc.start] : this.tok.start
+};
+
+LooseParser.prototype.startNodeAt = function startNodeAt (pos) {
+  if (this.options.locations) {
+    return new Node(this.toks, pos[0], pos[1])
+  } else {
+    return new Node(this.toks, pos)
+  }
+};
+
+LooseParser.prototype.finishNode = function finishNode (node, type) {
+  node.type = type;
+  node.end = this.last.end;
+  if (this.options.locations)
+    { node.loc.end = this.last.loc.end; }
+  if (this.options.ranges)
+    { node.range[1] = this.last.end; }
+  return node
+};
+
+LooseParser.prototype.dummyNode = function dummyNode (type) {
+  var dummy = this.startNode();
+  dummy.type = type;
+  dummy.end = dummy.start;
+  if (this.options.locations)
+    { dummy.loc.end = dummy.loc.start; }
+  if (this.options.ranges)
+    { dummy.range[1] = dummy.start; }
+  this.last = {type: tokTypes.name, start: dummy.start, end: dummy.start, loc: dummy.loc};
+  return dummy
+};
+
+LooseParser.prototype.dummyIdent = function dummyIdent () {
+  var dummy = this.dummyNode("Identifier");
+  dummy.name = "✖";
+  return dummy
+};
+
+LooseParser.prototype.dummyString = function dummyString () {
+  var dummy = this.dummyNode("Literal");
+  dummy.value = dummy.raw = "✖";
+  return dummy
+};
+
+LooseParser.prototype.eat = function eat (type) {
+  if (this.tok.type === type) {
+    this.next();
+    return true
+  } else {
+    return false
+  }
+};
+
+LooseParser.prototype.isContextual = function isContextual (name) {
+  return this.tok.type === tokTypes.name && this.tok.value === name
+};
+
+LooseParser.prototype.eatContextual = function eatContextual (name) {
+  return this.tok.value === name && this.eat(tokTypes.name)
+};
+
+LooseParser.prototype.canInsertSemicolon = function canInsertSemicolon () {
+  return this.tok.type === tokTypes.eof || this.tok.type === tokTypes.braceR ||
+    lineBreak.test(this.input.slice(this.last.end, this.tok.start))
+};
+
+LooseParser.prototype.semicolon = function semicolon () {
+  return this.eat(tokTypes.semi)
+};
+
+LooseParser.prototype.expect = function expect (type) {
+    var this$1 = this;
+
+  if (this.eat(type)) { return true }
+  for (var i = 1; i <= 2; i++) {
+    if (this$1.lookAhead(i).type == type) {
+      for (var j = 0; j < i; j++) { this$1.next(); }
+      return true
+    }
+  }
+};
+
+LooseParser.prototype.pushCx = function pushCx () {
+  this.context.push(this.curIndent);
+};
+
+LooseParser.prototype.popCx = function popCx () {
+  this.curIndent = this.context.pop();
+};
+
+LooseParser.prototype.lineEnd = function lineEnd (pos) {
+  while (pos < this.input.length && !isNewLine(this.input.charCodeAt(pos))) { ++pos; }
+  return pos
+};
+
+LooseParser.prototype.indentationAfter = function indentationAfter (pos) {
+    var this$1 = this;
+
+  for (var count = 0;; ++pos) {
+    var ch = this$1.input.charCodeAt(pos);
+    if (ch === 32) { ++count; }
+    else if (ch === 9) { count += this$1.options.tabSize; }
+    else { return count }
+  }
+};
+
+LooseParser.prototype.closes = function closes (closeTok, indent, line, blockHeuristic) {
+  if (this.tok.type === closeTok || this.tok.type === tokTypes.eof) { return true }
+  return line != this.curLineStart && this.curIndent < indent && this.tokenStartsLine() &&
+    (!blockHeuristic || this.nextLineStart >= this.input.length ||
+     this.indentationAfter(this.nextLineStart) < indent)
+};
+
+LooseParser.prototype.tokenStartsLine = function tokenStartsLine () {
+    var this$1 = this;
+
+  for (var p = this.tok.start - 1; p >= this.curLineStart; --p) {
+    var ch = this$1.input.charCodeAt(p);
+    if (ch !== 9 && ch !== 32) { return false }
+  }
+  return true
+};
+
+LooseParser.prototype.extend = function extend (name, f) {
+  this[name] = f(this[name]);
+};
+
+LooseParser.prototype.loadPlugins = function loadPlugins (pluginConfigs) {
+    var this$1 = this;
+
+  for (var name in pluginConfigs) {
+    var plugin = pluginsLoose[name];
+    if (!plugin) { throw new Error("Plugin '" + name + "' not found") }
+    plugin(this$1, pluginConfigs[name]);
+  }
+};
+
+LooseParser.prototype.parse = function parse () {
+  this.next();
+  return this.parseTopLevel()
+};
+
+var lp = LooseParser.prototype;
+
+function isSpace(ch) {
+  return (ch < 14 && ch > 8) || ch === 32 || ch === 160 || isNewLine(ch)
+}
+
+lp.next = function() {
+  var this$1 = this;
+
+  this.last = this.tok;
+  if (this.ahead.length)
+    { this.tok = this.ahead.shift(); }
+  else
+    { this.tok = this.readToken(); }
+
+  if (this.tok.start >= this.nextLineStart) {
+    while (this.tok.start >= this.nextLineStart) {
+      this$1.curLineStart = this$1.nextLineStart;
+      this$1.nextLineStart = this$1.lineEnd(this$1.curLineStart) + 1;
+    }
+    this.curIndent = this.indentationAfter(this.curLineStart);
+  }
+};
+
+lp.readToken = function() {
+  var this$1 = this;
+
+  for (;;) {
+    try {
+      this$1.toks.next();
+      if (this$1.toks.type === tokTypes.dot &&
+          this$1.input.substr(this$1.toks.end, 1) === "." &&
+          this$1.options.ecmaVersion >= 6) {
+        this$1.toks.end++;
+        this$1.toks.type = tokTypes.ellipsis;
+      }
+      return new Token(this$1.toks)
+    } catch (e) {
+      if (!(e instanceof SyntaxError)) { throw e }
+
+      // Try to skip some text, based on the error message, and then continue
+      var msg = e.message, pos = e.raisedAt, replace = true;
+      if (/unterminated/i.test(msg)) {
+        pos = this$1.lineEnd(e.pos + 1);
+        if (/string/.test(msg)) {
+          replace = {start: e.pos, end: pos, type: tokTypes.string, value: this$1.input.slice(e.pos + 1, pos)};
+        } else if (/regular expr/i.test(msg)) {
+          var re = this$1.input.slice(e.pos, pos);
+          try { re = new RegExp(re); } catch (e) { /* ignore compilation error due to new syntax */ }
+          replace = {start: e.pos, end: pos, type: tokTypes.regexp, value: re};
+        } else if (/template/.test(msg)) {
+          replace = {
+            start: e.pos,
+            end: pos,
+            type: tokTypes.template,
+            value: this$1.input.slice(e.pos, pos)
+          };
+        } else {
+          replace = false;
+        }
+      } else if (/invalid (unicode|regexp|number)|expecting unicode|octal literal|is reserved|directly after number|expected number in radix/i.test(msg)) {
+        while (pos < this.input.length && !isSpace(this.input.charCodeAt(pos))) { ++pos; }
+      } else if (/character escape|expected hexadecimal/i.test(msg)) {
+        while (pos < this.input.length) {
+          var ch = this$1.input.charCodeAt(pos++);
+          if (ch === 34 || ch === 39 || isNewLine(ch)) { break }
+        }
+      } else if (/unexpected character/i.test(msg)) {
+        pos++;
+        replace = false;
+      } else if (/regular expression/i.test(msg)) {
+        replace = true;
+      } else {
+        throw e
+      }
+      this$1.resetTo(pos);
+      if (replace === true) { replace = {start: pos, end: pos, type: tokTypes.name, value: "✖"}; }
+      if (replace) {
+        if (this$1.options.locations)
+          { replace.loc = new SourceLocation(
+            this$1.toks,
+            getLineInfo(this$1.input, replace.start),
+            getLineInfo(this$1.input, replace.end)); }
+        return replace
+      }
+    }
+  }
+};
+
+lp.resetTo = function(pos) {
+  var this$1 = this;
+
+  this.toks.pos = pos;
+  var ch = this.input.charAt(pos - 1);
+  this.toks.exprAllowed = !ch || /[[{(,;:?/*=+\-~!|&%^<>]/.test(ch) ||
+    /[enwfd]/.test(ch) &&
+    /\b(keywords|case|else|return|throw|new|in|(instance|type)of|delete|void)$/.test(this.input.slice(pos - 10, pos));
+
+  if (this.options.locations) {
+    this.toks.curLine = 1;
+    this.toks.lineStart = lineBreakG.lastIndex = 0;
+    var match;
+    while ((match = lineBreakG.exec(this.input)) && match.index < pos) {
+      ++this$1.toks.curLine;
+      this$1.toks.lineStart = match.index + match[0].length;
+    }
+  }
+};
+
+lp.lookAhead = function(n) {
+  var this$1 = this;
+
+  while (n > this.ahead.length)
+    { this$1.ahead.push(this$1.readToken()); }
+  return this.ahead[n - 1]
+};
+
+function isDummy(node) { return node.name == "✖" }
+
+var lp$1 = LooseParser.prototype;
+
+lp$1.parseTopLevel = function() {
+  var this$1 = this;
+
+  var node = this.startNodeAt(this.options.locations ? [0, getLineInfo(this.input, 0)] : 0);
+  node.body = [];
+  while (this.tok.type !== tokTypes.eof) { node.body.push(this$1.parseStatement()); }
+  this.toks.adaptDirectivePrologue(node.body);
+  this.last = this.tok;
+  if (this.options.ecmaVersion >= 6) {
+    node.sourceType = this.options.sourceType;
+  }
+  return this.finishNode(node, "Program")
+};
+
+lp$1.parseStatement = function() {
+  var this$1 = this;
+
+  var starttype = this.tok.type, node = this.startNode(), kind;
+
+  if (this.toks.isLet()) {
+    starttype = tokTypes._var;
+    kind = "let";
+  }
+
+  switch (starttype) {
+  case tokTypes._break: case tokTypes._continue:
+    this.next();
+    var isBreak = starttype === tokTypes._break;
+    if (this.semicolon() || this.canInsertSemicolon()) {
+      node.label = null;
+    } else {
+      node.label = this.tok.type === tokTypes.name ? this.parseIdent() : null;
+      this.semicolon();
+    }
+    return this.finishNode(node, isBreak ? "BreakStatement" : "ContinueStatement")
+
+  case tokTypes._debugger:
+    this.next();
+    this.semicolon();
+    return this.finishNode(node, "DebuggerStatement")
+
+  case tokTypes._do:
+    this.next();
+    node.body = this.parseStatement();
+    node.test = this.eat(tokTypes._while) ? this.parseParenExpression() : this.dummyIdent();
+    this.semicolon();
+    return this.finishNode(node, "DoWhileStatement")
+
+  case tokTypes._for:
+    this.next();
+    this.pushCx();
+    this.expect(tokTypes.parenL);
+    if (this.tok.type === tokTypes.semi) { return this.parseFor(node, null) }
+    var isLet = this.toks.isLet();
+    if (isLet || this.tok.type === tokTypes._var || this.tok.type === tokTypes._const) {
+      var init$1 = this.parseVar(true, isLet ? "let" : this.tok.value);
+      if (init$1.declarations.length === 1 && (this.tok.type === tokTypes._in || this.isContextual("of"))) {
+        return this.parseForIn(node, init$1)
+      }
+      return this.parseFor(node, init$1)
+    }
+    var init = this.parseExpression(true);
+    if (this.tok.type === tokTypes._in || this.isContextual("of"))
+      { return this.parseForIn(node, this.toAssignable(init)) }
+    return this.parseFor(node, init)
+
+  case tokTypes._function:
+    this.next();
+    return this.parseFunction(node, true)
+
+  case tokTypes._if:
+    this.next();
+    node.test = this.parseParenExpression();
+    node.consequent = this.parseStatement();
+    node.alternate = this.eat(tokTypes._else) ? this.parseStatement() : null;
+    return this.finishNode(node, "IfStatement")
+
+  case tokTypes._return:
+    this.next();
+    if (this.eat(tokTypes.semi) || this.canInsertSemicolon()) { node.argument = null; }
+    else { node.argument = this.parseExpression(); this.semicolon(); }
+    return this.finishNode(node, "ReturnStatement")
+
+  case tokTypes._switch:
+    var blockIndent = this.curIndent, line = this.curLineStart;
+    this.next();
+    node.discriminant = this.parseParenExpression();
+    node.cases = [];
+    this.pushCx();
+    this.expect(tokTypes.braceL);
+
+    var cur;
+    while (!this.closes(tokTypes.braceR, blockIndent, line, true)) {
+      if (this$1.tok.type === tokTypes._case || this$1.tok.type === tokTypes._default) {
+        var isCase = this$1.tok.type === tokTypes._case;
+        if (cur) { this$1.finishNode(cur, "SwitchCase"); }
+        node.cases.push(cur = this$1.startNode());
+        cur.consequent = [];
+        this$1.next();
+        if (isCase) { cur.test = this$1.parseExpression(); }
+        else { cur.test = null; }
+        this$1.expect(tokTypes.colon);
+      } else {
+        if (!cur) {
+          node.cases.push(cur = this$1.startNode());
+          cur.consequent = [];
+          cur.test = null;
+        }
+        cur.consequent.push(this$1.parseStatement());
+      }
+    }
+    if (cur) { this.finishNode(cur, "SwitchCase"); }
+    this.popCx();
+    this.eat(tokTypes.braceR);
+    return this.finishNode(node, "SwitchStatement")
+
+  case tokTypes._throw:
+    this.next();
+    node.argument = this.parseExpression();
+    this.semicolon();
+    return this.finishNode(node, "ThrowStatement")
+
+  case tokTypes._try:
+    this.next();
+    node.block = this.parseBlock();
+    node.handler = null;
+    if (this.tok.type === tokTypes._catch) {
+      var clause = this.startNode();
+      this.next();
+      this.expect(tokTypes.parenL);
+      clause.param = this.toAssignable(this.parseExprAtom(), true);
+      this.expect(tokTypes.parenR);
+      clause.body = this.parseBlock();
+      node.handler = this.finishNode(clause, "CatchClause");
+    }
+    node.finalizer = this.eat(tokTypes._finally) ? this.parseBlock() : null;
+    if (!node.handler && !node.finalizer) { return node.block }
+    return this.finishNode(node, "TryStatement")
+
+  case tokTypes._var:
+  case tokTypes._const:
+    return this.parseVar(false, kind || this.tok.value)
+
+  case tokTypes._while:
+    this.next();
+    node.test = this.parseParenExpression();
+    node.body = this.parseStatement();
+    return this.finishNode(node, "WhileStatement")
+
+  case tokTypes._with:
+    this.next();
+    node.object = this.parseParenExpression();
+    node.body = this.parseStatement();
+    return this.finishNode(node, "WithStatement")
+
+  case tokTypes.braceL:
+    return this.parseBlock()
+
+  case tokTypes.semi:
+    this.next();
+    return this.finishNode(node, "EmptyStatement")
+
+  case tokTypes._class:
+    return this.parseClass(true)
+
+  case tokTypes._import:
+    return this.parseImport()
+
+  case tokTypes._export:
+    return this.parseExport()
+
+  default:
+    if (this.toks.isAsyncFunction()) {
+      this.next();
+      this.next();
+      return this.parseFunction(node, true, true)
+    }
+    var expr = this.parseExpression();
+    if (isDummy(expr)) {
+      this.next();
+      if (this.tok.type === tokTypes.eof) { return this.finishNode(node, "EmptyStatement") }
+      return this.parseStatement()
+    } else if (starttype === tokTypes.name && expr.type === "Identifier" && this.eat(tokTypes.colon)) {
+      node.body = this.parseStatement();
+      node.label = expr;
+      return this.finishNode(node, "LabeledStatement")
+    } else {
+      node.expression = expr;
+      this.semicolon();
+      return this.finishNode(node, "ExpressionStatement")
+    }
+  }
+};
+
+lp$1.parseBlock = function() {
+  var this$1 = this;
+
+  var node = this.startNode();
+  this.pushCx();
+  this.expect(tokTypes.braceL);
+  var blockIndent = this.curIndent, line = this.curLineStart;
+  node.body = [];
+  while (!this.closes(tokTypes.braceR, blockIndent, line, true))
+    { node.body.push(this$1.parseStatement()); }
+  this.popCx();
+  this.eat(tokTypes.braceR);
+  return this.finishNode(node, "BlockStatement")
+};
+
+lp$1.parseFor = function(node, init) {
+  node.init = init;
+  node.test = node.update = null;
+  if (this.eat(tokTypes.semi) && this.tok.type !== tokTypes.semi) { node.test = this.parseExpression(); }
+  if (this.eat(tokTypes.semi) && this.tok.type !== tokTypes.parenR) { node.update = this.parseExpression(); }
+  this.popCx();
+  this.expect(tokTypes.parenR);
+  node.body = this.parseStatement();
+  return this.finishNode(node, "ForStatement")
+};
+
+lp$1.parseForIn = function(node, init) {
+  var type = this.tok.type === tokTypes._in ? "ForInStatement" : "ForOfStatement";
+  this.next();
+  node.left = init;
+  node.right = this.parseExpression();
+  this.popCx();
+  this.expect(tokTypes.parenR);
+  node.body = this.parseStatement();
+  return this.finishNode(node, type)
+};
+
+lp$1.parseVar = function(noIn, kind) {
+  var this$1 = this;
+
+  var node = this.startNode();
+  node.kind = kind;
+  this.next();
+  node.declarations = [];
+  do {
+    var decl = this$1.startNode();
+    decl.id = this$1.options.ecmaVersion >= 6 ? this$1.toAssignable(this$1.parseExprAtom(), true) : this$1.parseIdent();
+    decl.init = this$1.eat(tokTypes.eq) ? this$1.parseMaybeAssign(noIn) : null;
+    node.declarations.push(this$1.finishNode(decl, "VariableDeclarator"));
+  } while (this.eat(tokTypes.comma))
+  if (!node.declarations.length) {
+    var decl$1 = this.startNode();
+    decl$1.id = this.dummyIdent();
+    node.declarations.push(this.finishNode(decl$1, "VariableDeclarator"));
+  }
+  if (!noIn) { this.semicolon(); }
+  return this.finishNode(node, "VariableDeclaration")
+};
+
+lp$1.parseClass = function(isStatement) {
+  var this$1 = this;
+
+  var node = this.startNode();
+  this.next();
+  if (this.tok.type === tokTypes.name) { node.id = this.parseIdent(); }
+  else if (isStatement === true) { node.id = this.dummyIdent(); }
+  else { node.id = null; }
+  node.superClass = this.eat(tokTypes._extends) ? this.parseExpression() : null;
+  node.body = this.startNode();
+  node.body.body = [];
+  this.pushCx();
+  var indent = this.curIndent + 1, line = this.curLineStart;
+  this.eat(tokTypes.braceL);
+  if (this.curIndent + 1 < indent) { indent = this.curIndent; line = this.curLineStart; }
+  while (!this.closes(tokTypes.braceR, indent, line)) {
+    if (this$1.semicolon()) { continue }
+    var method = this$1.startNode(), isGenerator = (void 0), isAsync = (void 0);
+    if (this$1.options.ecmaVersion >= 6) {
+      method.static = false;
+      isGenerator = this$1.eat(tokTypes.star);
+    }
+    this$1.parsePropertyName(method);
+    if (isDummy(method.key)) { if (isDummy(this$1.parseMaybeAssign())) { this$1.next(); } this$1.eat(tokTypes.comma); continue }
+    if (method.key.type === "Identifier" && !method.computed && method.key.name === "static" &&
+        (this$1.tok.type != tokTypes.parenL && this$1.tok.type != tokTypes.braceL)) {
+      method.static = true;
+      isGenerator = this$1.eat(tokTypes.star);
+      this$1.parsePropertyName(method);
+    } else {
+      method.static = false;
+    }
+    if (!method.computed &&
+        method.key.type === "Identifier" && method.key.name === "async" && this$1.tok.type !== tokTypes.parenL &&
+        !this$1.canInsertSemicolon()) {
+      this$1.parsePropertyName(method);
+      isAsync = true;
+    } else {
+      isAsync = false;
+    }
+    if (this$1.options.ecmaVersion >= 5 && method.key.type === "Identifier" &&
+        !method.computed && (method.key.name === "get" || method.key.name === "set") &&
+        this$1.tok.type !== tokTypes.parenL && this$1.tok.type !== tokTypes.braceL) {
+      method.kind = method.key.name;
+      this$1.parsePropertyName(method);
+      method.value = this$1.parseMethod(false);
+    } else {
+      if (!method.computed && !method.static && !isGenerator && !isAsync && (
+        method.key.type === "Identifier" && method.key.name === "constructor" ||
+          method.key.type === "Literal" && method.key.value === "constructor")) {
+        method.kind = "constructor";
+      } else {
+        method.kind = "method";
+      }
+      method.value = this$1.parseMethod(isGenerator, isAsync);
+    }
+    node.body.body.push(this$1.finishNode(method, "MethodDefinition"));
+  }
+  this.popCx();
+  if (!this.eat(tokTypes.braceR)) {
+    // If there is no closing brace, make the node span to the start
+    // of the next token (this is useful for Tern)
+    this.last.end = this.tok.start;
+    if (this.options.locations) { this.last.loc.end = this.tok.loc.start; }
+  }
+  this.semicolon();
+  this.finishNode(node.body, "ClassBody");
+  return this.finishNode(node, isStatement ? "ClassDeclaration" : "ClassExpression")
+};
+
+lp$1.parseFunction = function(node, isStatement, isAsync) {
+  var oldInAsync = this.inAsync;
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 6) {
+    node.generator = this.eat(tokTypes.star);
+  }
+  if (this.options.ecmaVersion >= 8) {
+    node.async = !!isAsync;
+  }
+  if (this.tok.type === tokTypes.name) { node.id = this.parseIdent(); }
+  else if (isStatement === true) { node.id = this.dummyIdent(); }
+  this.inAsync = node.async;
+  node.params = this.parseFunctionParams();
+  node.body = this.parseBlock();
+  this.toks.adaptDirectivePrologue(node.body.body);
+  this.inAsync = oldInAsync;
+  return this.finishNode(node, isStatement ? "FunctionDeclaration" : "FunctionExpression")
+};
+
+lp$1.parseExport = function() {
+  var node = this.startNode();
+  this.next();
+  if (this.eat(tokTypes.star)) {
+    node.source = this.eatContextual("from") ? this.parseExprAtom() : this.dummyString();
+    return this.finishNode(node, "ExportAllDeclaration")
+  }
+  if (this.eat(tokTypes._default)) {
+    // export default (function foo() {}) // This is FunctionExpression.
+    var isAsync;
+    if (this.tok.type === tokTypes._function || (isAsync = this.toks.isAsyncFunction())) {
+      var fNode = this.startNode();
+      this.next();
+      if (isAsync) { this.next(); }
+      node.declaration = this.parseFunction(fNode, "nullableID", isAsync);
+    } else if (this.tok.type === tokTypes._class) {
+      node.declaration = this.parseClass("nullableID");
+    } else {
+      node.declaration = this.parseMaybeAssign();
+      this.semicolon();
+    }
+    return this.finishNode(node, "ExportDefaultDeclaration")
+  }
+  if (this.tok.type.keyword || this.toks.isLet() || this.toks.isAsyncFunction()) {
+    node.declaration = this.parseStatement();
+    node.specifiers = [];
+    node.source = null;
+  } else {
+    node.declaration = null;
+    node.specifiers = this.parseExportSpecifierList();
+    node.source = this.eatContextual("from") ? this.parseExprAtom() : null;
+    this.semicolon();
+  }
+  return this.finishNode(node, "ExportNamedDeclaration")
+};
+
+lp$1.parseImport = function() {
+  var node = this.startNode();
+  this.next();
+  if (this.tok.type === tokTypes.string) {
+    node.specifiers = [];
+    node.source = this.parseExprAtom();
+  } else {
+    var elt;
+    if (this.tok.type === tokTypes.name && this.tok.value !== "from") {
+      elt = this.startNode();
+      elt.local = this.parseIdent();
+      this.finishNode(elt, "ImportDefaultSpecifier");
+      this.eat(tokTypes.comma);
+    }
+    node.specifiers = this.parseImportSpecifierList();
+    node.source = this.eatContextual("from") && this.tok.type == tokTypes.string ? this.parseExprAtom() : this.dummyString();
+    if (elt) { node.specifiers.unshift(elt); }
+  }
+  this.semicolon();
+  return this.finishNode(node, "ImportDeclaration")
+};
+
+lp$1.parseImportSpecifierList = function() {
+  var this$1 = this;
+
+  var elts = [];
+  if (this.tok.type === tokTypes.star) {
+    var elt = this.startNode();
+    this.next();
+    elt.local = this.eatContextual("as") ? this.parseIdent() : this.dummyIdent();
+    elts.push(this.finishNode(elt, "ImportNamespaceSpecifier"));
+  } else {
+    var indent = this.curIndent, line = this.curLineStart, continuedLine = this.nextLineStart;
+    this.pushCx();
+    this.eat(tokTypes.braceL);
+    if (this.curLineStart > continuedLine) { continuedLine = this.curLineStart; }
+    while (!this.closes(tokTypes.braceR, indent + (this.curLineStart <= continuedLine ? 1 : 0), line)) {
+      var elt$1 = this$1.startNode();
+      if (this$1.eat(tokTypes.star)) {
+        elt$1.local = this$1.eatContextual("as") ? this$1.parseIdent() : this$1.dummyIdent();
+        this$1.finishNode(elt$1, "ImportNamespaceSpecifier");
+      } else {
+        if (this$1.isContextual("from")) { break }
+        elt$1.imported = this$1.parseIdent();
+        if (isDummy(elt$1.imported)) { break }
+        elt$1.local = this$1.eatContextual("as") ? this$1.parseIdent() : elt$1.imported;
+        this$1.finishNode(elt$1, "ImportSpecifier");
+      }
+      elts.push(elt$1);
+      this$1.eat(tokTypes.comma);
+    }
+    this.eat(tokTypes.braceR);
+    this.popCx();
+  }
+  return elts
+};
+
+lp$1.parseExportSpecifierList = function() {
+  var this$1 = this;
+
+  var elts = [];
+  var indent = this.curIndent, line = this.curLineStart, continuedLine = this.nextLineStart;
+  this.pushCx();
+  this.eat(tokTypes.braceL);
+  if (this.curLineStart > continuedLine) { continuedLine = this.curLineStart; }
+  while (!this.closes(tokTypes.braceR, indent + (this.curLineStart <= continuedLine ? 1 : 0), line)) {
+    if (this$1.isContextual("from")) { break }
+    var elt = this$1.startNode();
+    elt.local = this$1.parseIdent();
+    if (isDummy(elt.local)) { break }
+    elt.exported = this$1.eatContextual("as") ? this$1.parseIdent() : elt.local;
+    this$1.finishNode(elt, "ExportSpecifier");
+    elts.push(elt);
+    this$1.eat(tokTypes.comma);
+  }
+  this.eat(tokTypes.braceR);
+  this.popCx();
+  return elts
+};
+
+var lp$2 = LooseParser.prototype;
+
+lp$2.checkLVal = function(expr) {
+  if (!expr) { return expr }
+  switch (expr.type) {
+  case "Identifier":
+  case "MemberExpression":
+    return expr
+
+  case "ParenthesizedExpression":
+    expr.expression = this.checkLVal(expr.expression);
+    return expr
+
+  default:
+    return this.dummyIdent()
+  }
+};
+
+lp$2.parseExpression = function(noIn) {
+  var this$1 = this;
+
+  var start = this.storeCurrentPos();
+  var expr = this.parseMaybeAssign(noIn);
+  if (this.tok.type === tokTypes.comma) {
+    var node = this.startNodeAt(start);
+    node.expressions = [expr];
+    while (this.eat(tokTypes.comma)) { node.expressions.push(this$1.parseMaybeAssign(noIn)); }
+    return this.finishNode(node, "SequenceExpression")
+  }
+  return expr
+};
+
+lp$2.parseParenExpression = function() {
+  this.pushCx();
+  this.expect(tokTypes.parenL);
+  var val = this.parseExpression();
+  this.popCx();
+  this.expect(tokTypes.parenR);
+  return val
+};
+
+lp$2.parseMaybeAssign = function(noIn) {
+  if (this.toks.isContextual("yield")) {
+    var node = this.startNode();
+    this.next();
+    if (this.semicolon() || this.canInsertSemicolon() || (this.tok.type != tokTypes.star && !this.tok.type.startsExpr)) {
+      node.delegate = false;
+      node.argument = null;
+    } else {
+      node.delegate = this.eat(tokTypes.star);
+      node.argument = this.parseMaybeAssign();
+    }
+    return this.finishNode(node, "YieldExpression")
+  }
+
+  var start = this.storeCurrentPos();
+  var left = this.parseMaybeConditional(noIn);
+  if (this.tok.type.isAssign) {
+    var node$1 = this.startNodeAt(start);
+    node$1.operator = this.tok.value;
+    node$1.left = this.tok.type === tokTypes.eq ? this.toAssignable(left) : this.checkLVal(left);
+    this.next();
+    node$1.right = this.parseMaybeAssign(noIn);
+    return this.finishNode(node$1, "AssignmentExpression")
+  }
+  return left
+};
+
+lp$2.parseMaybeConditional = function(noIn) {
+  var start = this.storeCurrentPos();
+  var expr = this.parseExprOps(noIn);
+  if (this.eat(tokTypes.question)) {
+    var node = this.startNodeAt(start);
+    node.test = expr;
+    node.consequent = this.parseMaybeAssign();
+    node.alternate = this.expect(tokTypes.colon) ? this.parseMaybeAssign(noIn) : this.dummyIdent();
+    return this.finishNode(node, "ConditionalExpression")
+  }
+  return expr
+};
+
+lp$2.parseExprOps = function(noIn) {
+  var start = this.storeCurrentPos();
+  var indent = this.curIndent, line = this.curLineStart;
+  return this.parseExprOp(this.parseMaybeUnary(false), start, -1, noIn, indent, line)
+};
+
+lp$2.parseExprOp = function(left, start, minPrec, noIn, indent, line) {
+  if (this.curLineStart != line && this.curIndent < indent && this.tokenStartsLine()) { return left }
+  var prec = this.tok.type.binop;
+  if (prec != null && (!noIn || this.tok.type !== tokTypes._in)) {
+    if (prec > minPrec) {
+      var node = this.startNodeAt(start);
+      node.left = left;
+      node.operator = this.tok.value;
+      this.next();
+      if (this.curLineStart != line && this.curIndent < indent && this.tokenStartsLine()) {
+        node.right = this.dummyIdent();
+      } else {
+        var rightStart = this.storeCurrentPos();
+        node.right = this.parseExprOp(this.parseMaybeUnary(false), rightStart, prec, noIn, indent, line);
+      }
+      this.finishNode(node, /&&|\|\|/.test(node.operator) ? "LogicalExpression" : "BinaryExpression");
+      return this.parseExprOp(node, start, minPrec, noIn, indent, line)
+    }
+  }
+  return left
+};
+
+lp$2.parseMaybeUnary = function(sawUnary) {
+  var this$1 = this;
+
+  var start = this.storeCurrentPos(), expr;
+  if (this.options.ecmaVersion >= 8 && this.inAsync && this.toks.isContextual("await")) {
+    expr = this.parseAwait();
+    sawUnary = true;
+  } else if (this.tok.type.prefix) {
+    var node = this.startNode(), update = this.tok.type === tokTypes.incDec;
+    if (!update) { sawUnary = true; }
+    node.operator = this.tok.value;
+    node.prefix = true;
+    this.next();
+    node.argument = this.parseMaybeUnary(true);
+    if (update) { node.argument = this.checkLVal(node.argument); }
+    expr = this.finishNode(node, update ? "UpdateExpression" : "UnaryExpression");
+  } else if (this.tok.type === tokTypes.ellipsis) {
+    var node$1 = this.startNode();
+    this.next();
+    node$1.argument = this.parseMaybeUnary(sawUnary);
+    expr = this.finishNode(node$1, "SpreadElement");
+  } else {
+    expr = this.parseExprSubscripts();
+    while (this.tok.type.postfix && !this.canInsertSemicolon()) {
+      var node$2 = this$1.startNodeAt(start);
+      node$2.operator = this$1.tok.value;
+      node$2.prefix = false;
+      node$2.argument = this$1.checkLVal(expr);
+      this$1.next();
+      expr = this$1.finishNode(node$2, "UpdateExpression");
+    }
+  }
+
+  if (!sawUnary && this.eat(tokTypes.starstar)) {
+    var node$3 = this.startNodeAt(start);
+    node$3.operator = "**";
+    node$3.left = expr;
+    node$3.right = this.parseMaybeUnary(false);
+    return this.finishNode(node$3, "BinaryExpression")
+  }
+
+  return expr
+};
+
+lp$2.parseExprSubscripts = function() {
+  var start = this.storeCurrentPos();
+  return this.parseSubscripts(this.parseExprAtom(), start, false, this.curIndent, this.curLineStart)
+};
+
+lp$2.parseSubscripts = function(base, start, noCalls, startIndent, line) {
+  var this$1 = this;
+
+  for (;;) {
+    if (this$1.curLineStart != line && this$1.curIndent <= startIndent && this$1.tokenStartsLine()) {
+      if (this$1.tok.type == tokTypes.dot && this$1.curIndent == startIndent)
+        { --startIndent; }
+      else
+        { return base }
+    }
+
+    var maybeAsyncArrow = base.type === "Identifier" && base.name === "async" && !this$1.canInsertSemicolon();
+
+    if (this$1.eat(tokTypes.dot)) {
+      var node = this$1.startNodeAt(start);
+      node.object = base;
+      if (this$1.curLineStart != line && this$1.curIndent <= startIndent && this$1.tokenStartsLine())
+        { node.property = this$1.dummyIdent(); }
+      else
+        { node.property = this$1.parsePropertyAccessor() || this$1.dummyIdent(); }
+      node.computed = false;
+      base = this$1.finishNode(node, "MemberExpression");
+    } else if (this$1.tok.type == tokTypes.bracketL) {
+      this$1.pushCx();
+      this$1.next();
+      var node$1 = this$1.startNodeAt(start);
+      node$1.object = base;
+      node$1.property = this$1.parseExpression();
+      node$1.computed = true;
+      this$1.popCx();
+      this$1.expect(tokTypes.bracketR);
+      base = this$1.finishNode(node$1, "MemberExpression");
+    } else if (!noCalls && this$1.tok.type == tokTypes.parenL) {
+      var exprList = this$1.parseExprList(tokTypes.parenR);
+      if (maybeAsyncArrow && this$1.eat(tokTypes.arrow))
+        { return this$1.parseArrowExpression(this$1.startNodeAt(start), exprList, true) }
+      var node$2 = this$1.startNodeAt(start);
+      node$2.callee = base;
+      node$2.arguments = exprList;
+      base = this$1.finishNode(node$2, "CallExpression");
+    } else if (this$1.tok.type == tokTypes.backQuote) {
+      var node$3 = this$1.startNodeAt(start);
+      node$3.tag = base;
+      node$3.quasi = this$1.parseTemplate();
+      base = this$1.finishNode(node$3, "TaggedTemplateExpression");
+    } else {
+      return base
+    }
+  }
+};
+
+lp$2.parseExprAtom = function() {
+  var node;
+  switch (this.tok.type) {
+  case tokTypes._this:
+  case tokTypes._super:
+    var type = this.tok.type === tokTypes._this ? "ThisExpression" : "Super";
+    node = this.startNode();
+    this.next();
+    return this.finishNode(node, type)
+
+  case tokTypes.name:
+    var start = this.storeCurrentPos();
+    var id = this.parseIdent();
+    var isAsync = false;
+    if (id.name === "async" && !this.canInsertSemicolon()) {
+      if (this.eat(tokTypes._function))
+        { return this.parseFunction(this.startNodeAt(start), false, true) }
+      if (this.tok.type === tokTypes.name) {
+        id = this.parseIdent();
+        isAsync = true;
+      }
+    }
+    return this.eat(tokTypes.arrow) ? this.parseArrowExpression(this.startNodeAt(start), [id], isAsync) : id
+
+  case tokTypes.regexp:
+    node = this.startNode();
+    var val = this.tok.value;
+    node.regex = {pattern: val.pattern, flags: val.flags};
+    node.value = val.value;
+    node.raw = this.input.slice(this.tok.start, this.tok.end);
+    this.next();
+    return this.finishNode(node, "Literal")
+
+  case tokTypes.num: case tokTypes.string:
+    node = this.startNode();
+    node.value = this.tok.value;
+    node.raw = this.input.slice(this.tok.start, this.tok.end);
+    this.next();
+    return this.finishNode(node, "Literal")
+
+  case tokTypes._null: case tokTypes._true: case tokTypes._false:
+    node = this.startNode();
+    node.value = this.tok.type === tokTypes._null ? null : this.tok.type === tokTypes._true;
+    node.raw = this.tok.type.keyword;
+    this.next();
+    return this.finishNode(node, "Literal")
+
+  case tokTypes.parenL:
+    var parenStart = this.storeCurrentPos();
+    this.next();
+    var inner = this.parseExpression();
+    this.expect(tokTypes.parenR);
+    if (this.eat(tokTypes.arrow)) {
+      // (a,)=>a // SequenceExpression makes dummy in the last hole. Drop the dummy.
+      var params = inner.expressions || [inner];
+      if (params.length && isDummy(params[params.length - 1]))
+        { params.pop(); }
+      return this.parseArrowExpression(this.startNodeAt(parenStart), params)
+    }
+    if (this.options.preserveParens) {
+      var par = this.startNodeAt(parenStart);
+      par.expression = inner;
+      inner = this.finishNode(par, "ParenthesizedExpression");
+    }
+    return inner
+
+  case tokTypes.bracketL:
+    node = this.startNode();
+    node.elements = this.parseExprList(tokTypes.bracketR, true);
+    return this.finishNode(node, "ArrayExpression")
+
+  case tokTypes.braceL:
+    return this.parseObj()
+
+  case tokTypes._class:
+    return this.parseClass(false)
+
+  case tokTypes._function:
+    node = this.startNode();
+    this.next();
+    return this.parseFunction(node, false)
+
+  case tokTypes._new:
+    return this.parseNew()
+
+  case tokTypes.backQuote:
+    return this.parseTemplate()
+
+  default:
+    return this.dummyIdent()
+  }
+};
+
+lp$2.parseNew = function() {
+  var node = this.startNode(), startIndent = this.curIndent, line = this.curLineStart;
+  var meta = this.parseIdent(true);
+  if (this.options.ecmaVersion >= 6 && this.eat(tokTypes.dot)) {
+    node.meta = meta;
+    node.property = this.parseIdent(true);
+    return this.finishNode(node, "MetaProperty")
+  }
+  var start = this.storeCurrentPos();
+  node.callee = this.parseSubscripts(this.parseExprAtom(), start, true, startIndent, line);
+  if (this.tok.type == tokTypes.parenL) {
+    node.arguments = this.parseExprList(tokTypes.parenR);
+  } else {
+    node.arguments = [];
+  }
+  return this.finishNode(node, "NewExpression")
+};
+
+lp$2.parseTemplateElement = function() {
+  var elem = this.startNode();
+
+  // The loose parser accepts invalid unicode escapes even in untagged templates.
+  if (this.tok.type === tokTypes.invalidTemplate) {
+    elem.value = {
+      raw: this.tok.value,
+      cooked: null
+    };
+  } else {
+    elem.value = {
+      raw: this.input.slice(this.tok.start, this.tok.end).replace(/\r\n?/g, "\n"),
+      cooked: this.tok.value
+    };
+  }
+  this.next();
+  elem.tail = this.tok.type === tokTypes.backQuote;
+  return this.finishNode(elem, "TemplateElement")
+};
+
+lp$2.parseTemplate = function() {
+  var this$1 = this;
+
+  var node = this.startNode();
+  this.next();
+  node.expressions = [];
+  var curElt = this.parseTemplateElement();
+  node.quasis = [curElt];
+  while (!curElt.tail) {
+    this$1.next();
+    node.expressions.push(this$1.parseExpression());
+    if (this$1.expect(tokTypes.braceR)) {
+      curElt = this$1.parseTemplateElement();
+    } else {
+      curElt = this$1.startNode();
+      curElt.value = {cooked: "", raw: ""};
+      curElt.tail = true;
+      this$1.finishNode(curElt, "TemplateElement");
+    }
+    node.quasis.push(curElt);
+  }
+  this.expect(tokTypes.backQuote);
+  return this.finishNode(node, "TemplateLiteral")
+};
+
+lp$2.parseObj = function() {
+  var this$1 = this;
+
+  var node = this.startNode();
+  node.properties = [];
+  this.pushCx();
+  var indent = this.curIndent + 1, line = this.curLineStart;
+  this.eat(tokTypes.braceL);
+  if (this.curIndent + 1 < indent) { indent = this.curIndent; line = this.curLineStart; }
+  while (!this.closes(tokTypes.braceR, indent, line)) {
+    var prop = this$1.startNode(), isGenerator = (void 0), isAsync = (void 0), start = (void 0);
+    if (this$1.options.ecmaVersion >= 6) {
+      start = this$1.storeCurrentPos();
+      prop.method = false;
+      prop.shorthand = false;
+      isGenerator = this$1.eat(tokTypes.star);
+    }
+    this$1.parsePropertyName(prop);
+    if (this$1.toks.isAsyncProp(prop)) {
+      this$1.parsePropertyName(prop);
+      isAsync = true;
+    } else {
+      isAsync = false;
+    }
+    if (isDummy(prop.key)) { if (isDummy(this$1.parseMaybeAssign())) { this$1.next(); } this$1.eat(tokTypes.comma); continue }
+    if (this$1.eat(tokTypes.colon)) {
+      prop.kind = "init";
+      prop.value = this$1.parseMaybeAssign();
+    } else if (this$1.options.ecmaVersion >= 6 && (this$1.tok.type === tokTypes.parenL || this$1.tok.type === tokTypes.braceL)) {
+      prop.kind = "init";
+      prop.method = true;
+      prop.value = this$1.parseMethod(isGenerator, isAsync);
+    } else if (this$1.options.ecmaVersion >= 5 && prop.key.type === "Identifier" &&
+               !prop.computed && (prop.key.name === "get" || prop.key.name === "set") &&
+               (this$1.tok.type != tokTypes.comma && this$1.tok.type != tokTypes.braceR && this$1.tok.type != tokTypes.eq)) {
+      prop.kind = prop.key.name;
+      this$1.parsePropertyName(prop);
+      prop.value = this$1.parseMethod(false);
+    } else {
+      prop.kind = "init";
+      if (this$1.options.ecmaVersion >= 6) {
+        if (this$1.eat(tokTypes.eq)) {
+          var assign = this$1.startNodeAt(start);
+          assign.operator = "=";
+          assign.left = prop.key;
+          assign.right = this$1.parseMaybeAssign();
+          prop.value = this$1.finishNode(assign, "AssignmentExpression");
+        } else {
+          prop.value = prop.key;
+        }
+      } else {
+        prop.value = this$1.dummyIdent();
+      }
+      prop.shorthand = true;
+    }
+    node.properties.push(this$1.finishNode(prop, "Property"));
+    this$1.eat(tokTypes.comma);
+  }
+  this.popCx();
+  if (!this.eat(tokTypes.braceR)) {
+    // If there is no closing brace, make the node span to the start
+    // of the next token (this is useful for Tern)
+    this.last.end = this.tok.start;
+    if (this.options.locations) { this.last.loc.end = this.tok.loc.start; }
+  }
+  return this.finishNode(node, "ObjectExpression")
+};
+
+lp$2.parsePropertyName = function(prop) {
+  if (this.options.ecmaVersion >= 6) {
+    if (this.eat(tokTypes.bracketL)) {
+      prop.computed = true;
+      prop.key = this.parseExpression();
+      this.expect(tokTypes.bracketR);
+      return
+    } else {
+      prop.computed = false;
+    }
+  }
+  var key = (this.tok.type === tokTypes.num || this.tok.type === tokTypes.string) ? this.parseExprAtom() : this.parseIdent();
+  prop.key = key || this.dummyIdent();
+};
+
+lp$2.parsePropertyAccessor = function() {
+  if (this.tok.type === tokTypes.name || this.tok.type.keyword) { return this.parseIdent() }
+};
+
+lp$2.parseIdent = function() {
+  var name = this.tok.type === tokTypes.name ? this.tok.value : this.tok.type.keyword;
+  if (!name) { return this.dummyIdent() }
+  var node = this.startNode();
+  this.next();
+  node.name = name;
+  return this.finishNode(node, "Identifier")
+};
+
+lp$2.initFunction = function(node) {
+  node.id = null;
+  node.params = [];
+  if (this.options.ecmaVersion >= 6) {
+    node.generator = false;
+    node.expression = false;
+  }
+  if (this.options.ecmaVersion >= 8)
+    { node.async = false; }
+};
+
+// Convert existing expression atom to assignable pattern
+// if possible.
+
+lp$2.toAssignable = function(node, binding) {
+  var this$1 = this;
+
+  if (!node || node.type == "Identifier" || (node.type == "MemberExpression" && !binding)) {
+    // Okay
+  } else if (node.type == "ParenthesizedExpression") {
+    this.toAssignable(node.expression, binding);
+  } else if (this.options.ecmaVersion < 6) {
+    return this.dummyIdent()
+  } else if (node.type == "ObjectExpression") {
+    node.type = "ObjectPattern";
+    var props = node.properties;
+    for (var i = 0, list = props; i < list.length; i += 1)
+      {
+      var prop = list[i];
+
+      this$1.toAssignable(prop.value, binding);
+    }
+  } else if (node.type == "ArrayExpression") {
+    node.type = "ArrayPattern";
+    this.toAssignableList(node.elements, binding);
+  } else if (node.type == "SpreadElement") {
+    node.type = "RestElement";
+    this.toAssignable(node.argument, binding);
+  } else if (node.type == "AssignmentExpression") {
+    node.type = "AssignmentPattern";
+    delete node.operator;
+  } else {
+    return this.dummyIdent()
+  }
+  return node
+};
+
+lp$2.toAssignableList = function(exprList, binding) {
+  var this$1 = this;
+
+  for (var i = 0, list = exprList; i < list.length; i += 1)
+    {
+    var expr = list[i];
+
+    this$1.toAssignable(expr, binding);
+  }
+  return exprList
+};
+
+lp$2.parseFunctionParams = function(params) {
+  params = this.parseExprList(tokTypes.parenR);
+  return this.toAssignableList(params, true)
+};
+
+lp$2.parseMethod = function(isGenerator, isAsync) {
+  var node = this.startNode(), oldInAsync = this.inAsync;
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 6)
+    { node.generator = !!isGenerator; }
+  if (this.options.ecmaVersion >= 8)
+    { node.async = !!isAsync; }
+  this.inAsync = node.async;
+  node.params = this.parseFunctionParams();
+  node.body = this.parseBlock();
+  this.toks.adaptDirectivePrologue(node.body.body);
+  this.inAsync = oldInAsync;
+  return this.finishNode(node, "FunctionExpression")
+};
+
+lp$2.parseArrowExpression = function(node, params, isAsync) {
+  var oldInAsync = this.inAsync;
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 8)
+    { node.async = !!isAsync; }
+  this.inAsync = node.async;
+  node.params = this.toAssignableList(params, true);
+  node.expression = this.tok.type !== tokTypes.braceL;
+  if (node.expression) {
+    node.body = this.parseMaybeAssign();
+  } else {
+    node.body = this.parseBlock();
+    this.toks.adaptDirectivePrologue(node.body.body);
+  }
+  this.inAsync = oldInAsync;
+  return this.finishNode(node, "ArrowFunctionExpression")
+};
+
+lp$2.parseExprList = function(close, allowEmpty) {
+  var this$1 = this;
+
+  this.pushCx();
+  var indent = this.curIndent, line = this.curLineStart, elts = [];
+  this.next(); // Opening bracket
+  while (!this.closes(close, indent + 1, line)) {
+    if (this$1.eat(tokTypes.comma)) {
+      elts.push(allowEmpty ? null : this$1.dummyIdent());
+      continue
+    }
+    var elt = this$1.parseMaybeAssign();
+    if (isDummy(elt)) {
+      if (this$1.closes(close, indent, line)) { break }
+      this$1.next();
+    } else {
+      elts.push(elt);
+    }
+    this$1.eat(tokTypes.comma);
+  }
+  this.popCx();
+  if (!this.eat(close)) {
+    // If there is no closing brace, make the node span to the start
+    // of the next token (this is useful for Tern)
+    this.last.end = this.tok.start;
+    if (this.options.locations) { this.last.loc.end = this.tok.loc.start; }
+  }
+  return elts
+};
+
+lp$2.parseAwait = function() {
+  var node = this.startNode();
+  this.next();
+  node.argument = this.parseMaybeUnary();
+  return this.finishNode(node, "AwaitExpression")
+};
+
+// Acorn: Loose parser
+//
+// This module provides an alternative parser (`parse_dammit`) that
+// exposes that same interface as `parse`, but will try to parse
+// anything as JavaScript, repairing syntax error the best it can.
+// There are circumstances in which it will raise an error and give
+// up, but they are very rare. The resulting AST will be a mostly
+// valid JavaScript AST (as per the [Mozilla parser API][api], except
+// that:
+//
+// - Return outside functions is allowed
+//
+// - Label consistency (no conflicts, break only to existing labels)
+//   is not enforced.
+//
+// - Bogus Identifier nodes with a name of `"✖"` are inserted whenever
+//   the parser got too confused to return anything meaningful.
+//
+// [api]: https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API
+//
+// The expected use for this is to *first* try `acorn.parse`, and only
+// if that fails switch to `parse_dammit`. The loose parser might
+// parse badly indented code incorrectly, so **don't** use it as
+// your default parser.
+//
+// Quite a lot of acorn.js is duplicated here. The alternative was to
+// add a *lot* of extra cruft to that file, making it less readable
+// and slower. Copying and editing the code allowed me to make
+// invasive changes and simplifications without creating a complicated
+// tangle.
+
+defaultOptions.tabSize = 4;
+
+// eslint-disable-next-line camelcase
+function parse_dammit(input, options) {
+  return new LooseParser(input, options).parse()
+}
+
+addLooseExports(parse_dammit, LooseParser, pluginsLoose);
+
+export { parse_dammit, LooseParser, pluginsLoose };
diff --git a/deps/acorn/dist/acorn_loose.js b/deps/acorn/dist/acorn_loose.js
new file mode 100644
index 0000000000..d6738db9dc
--- /dev/null
+++ b/deps/acorn/dist/acorn_loose.js
@@ -0,0 +1,1400 @@
+(function (global, factory) {
+	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports, require('./acorn')) :
+	typeof define === 'function' && define.amd ? define(['exports', './acorn'], factory) :
+	(factory((global.acorn = global.acorn || {}, global.acorn.loose = global.acorn.loose || {}),global.acorn));
+}(this, (function (exports,__acorn) { 'use strict';
+
+// Registered plugins
+var pluginsLoose = {};
+
+var LooseParser = function LooseParser(input, options) {
+  if ( options === void 0 ) options = {};
+
+  this.toks = __acorn.tokenizer(input, options);
+  this.options = this.toks.options;
+  this.input = this.toks.input;
+  this.tok = this.last = {type: __acorn.tokTypes.eof, start: 0, end: 0};
+  if (this.options.locations) {
+    var here = this.toks.curPosition();
+    this.tok.loc = new __acorn.SourceLocation(this.toks, here, here);
+  }
+  this.ahead = []; // Tokens ahead
+  this.context = []; // Indentation contexted
+  this.curIndent = 0;
+  this.curLineStart = 0;
+  this.nextLineStart = this.lineEnd(this.curLineStart) + 1;
+  this.inAsync = false;
+  // Load plugins
+  this.options.pluginsLoose = options.pluginsLoose || {};
+  this.loadPlugins(this.options.pluginsLoose);
+};
+
+LooseParser.prototype.startNode = function startNode () {
+  return new __acorn.Node(this.toks, this.tok.start, this.options.locations ? this.tok.loc.start : null)
+};
+
+LooseParser.prototype.storeCurrentPos = function storeCurrentPos () {
+  return this.options.locations ? [this.tok.start, this.tok.loc.start] : this.tok.start
+};
+
+LooseParser.prototype.startNodeAt = function startNodeAt (pos) {
+  if (this.options.locations) {
+    return new __acorn.Node(this.toks, pos[0], pos[1])
+  } else {
+    return new __acorn.Node(this.toks, pos)
+  }
+};
+
+LooseParser.prototype.finishNode = function finishNode (node, type) {
+  node.type = type;
+  node.end = this.last.end;
+  if (this.options.locations)
+    { node.loc.end = this.last.loc.end; }
+  if (this.options.ranges)
+    { node.range[1] = this.last.end; }
+  return node
+};
+
+LooseParser.prototype.dummyNode = function dummyNode (type) {
+  var dummy = this.startNode();
+  dummy.type = type;
+  dummy.end = dummy.start;
+  if (this.options.locations)
+    { dummy.loc.end = dummy.loc.start; }
+  if (this.options.ranges)
+    { dummy.range[1] = dummy.start; }
+  this.last = {type: __acorn.tokTypes.name, start: dummy.start, end: dummy.start, loc: dummy.loc};
+  return dummy
+};
+
+LooseParser.prototype.dummyIdent = function dummyIdent () {
+  var dummy = this.dummyNode("Identifier");
+  dummy.name = "✖";
+  return dummy
+};
+
+LooseParser.prototype.dummyString = function dummyString () {
+  var dummy = this.dummyNode("Literal");
+  dummy.value = dummy.raw = "✖";
+  return dummy
+};
+
+LooseParser.prototype.eat = function eat (type) {
+  if (this.tok.type === type) {
+    this.next();
+    return true
+  } else {
+    return false
+  }
+};
+
+LooseParser.prototype.isContextual = function isContextual (name) {
+  return this.tok.type === __acorn.tokTypes.name && this.tok.value === name
+};
+
+LooseParser.prototype.eatContextual = function eatContextual (name) {
+  return this.tok.value === name && this.eat(__acorn.tokTypes.name)
+};
+
+LooseParser.prototype.canInsertSemicolon = function canInsertSemicolon () {
+  return this.tok.type === __acorn.tokTypes.eof || this.tok.type === __acorn.tokTypes.braceR ||
+    __acorn.lineBreak.test(this.input.slice(this.last.end, this.tok.start))
+};
+
+LooseParser.prototype.semicolon = function semicolon () {
+  return this.eat(__acorn.tokTypes.semi)
+};
+
+LooseParser.prototype.expect = function expect (type) {
+    var this$1 = this;
+
+  if (this.eat(type)) { return true }
+  for (var i = 1; i <= 2; i++) {
+    if (this$1.lookAhead(i).type == type) {
+      for (var j = 0; j < i; j++) { this$1.next(); }
+      return true
+    }
+  }
+};
+
+LooseParser.prototype.pushCx = function pushCx () {
+  this.context.push(this.curIndent);
+};
+
+LooseParser.prototype.popCx = function popCx () {
+  this.curIndent = this.context.pop();
+};
+
+LooseParser.prototype.lineEnd = function lineEnd (pos) {
+  while (pos < this.input.length && !__acorn.isNewLine(this.input.charCodeAt(pos))) { ++pos; }
+  return pos
+};
+
+LooseParser.prototype.indentationAfter = function indentationAfter (pos) {
+    var this$1 = this;
+
+  for (var count = 0;; ++pos) {
+    var ch = this$1.input.charCodeAt(pos);
+    if (ch === 32) { ++count; }
+    else if (ch === 9) { count += this$1.options.tabSize; }
+    else { return count }
+  }
+};
+
+LooseParser.prototype.closes = function closes (closeTok, indent, line, blockHeuristic) {
+  if (this.tok.type === closeTok || this.tok.type === __acorn.tokTypes.eof) { return true }
+  return line != this.curLineStart && this.curIndent < indent && this.tokenStartsLine() &&
+    (!blockHeuristic || this.nextLineStart >= this.input.length ||
+     this.indentationAfter(this.nextLineStart) < indent)
+};
+
+LooseParser.prototype.tokenStartsLine = function tokenStartsLine () {
+    var this$1 = this;
+
+  for (var p = this.tok.start - 1; p >= this.curLineStart; --p) {
+    var ch = this$1.input.charCodeAt(p);
+    if (ch !== 9 && ch !== 32) { return false }
+  }
+  return true
+};
+
+LooseParser.prototype.extend = function extend (name, f) {
+  this[name] = f(this[name]);
+};
+
+LooseParser.prototype.loadPlugins = function loadPlugins (pluginConfigs) {
+    var this$1 = this;
+
+  for (var name in pluginConfigs) {
+    var plugin = pluginsLoose[name];
+    if (!plugin) { throw new Error("Plugin '" + name + "' not found") }
+    plugin(this$1, pluginConfigs[name]);
+  }
+};
+
+LooseParser.prototype.parse = function parse () {
+  this.next();
+  return this.parseTopLevel()
+};
+
+var lp = LooseParser.prototype;
+
+function isSpace(ch) {
+  return (ch < 14 && ch > 8) || ch === 32 || ch === 160 || __acorn.isNewLine(ch)
+}
+
+lp.next = function() {
+  var this$1 = this;
+
+  this.last = this.tok;
+  if (this.ahead.length)
+    { this.tok = this.ahead.shift(); }
+  else
+    { this.tok = this.readToken(); }
+
+  if (this.tok.start >= this.nextLineStart) {
+    while (this.tok.start >= this.nextLineStart) {
+      this$1.curLineStart = this$1.nextLineStart;
+      this$1.nextLineStart = this$1.lineEnd(this$1.curLineStart) + 1;
+    }
+    this.curIndent = this.indentationAfter(this.curLineStart);
+  }
+};
+
+lp.readToken = function() {
+  var this$1 = this;
+
+  for (;;) {
+    try {
+      this$1.toks.next();
+      if (this$1.toks.type === __acorn.tokTypes.dot &&
+          this$1.input.substr(this$1.toks.end, 1) === "." &&
+          this$1.options.ecmaVersion >= 6) {
+        this$1.toks.end++;
+        this$1.toks.type = __acorn.tokTypes.ellipsis;
+      }
+      return new __acorn.Token(this$1.toks)
+    } catch (e) {
+      if (!(e instanceof SyntaxError)) { throw e }
+
+      // Try to skip some text, based on the error message, and then continue
+      var msg = e.message, pos = e.raisedAt, replace = true;
+      if (/unterminated/i.test(msg)) {
+        pos = this$1.lineEnd(e.pos + 1);
+        if (/string/.test(msg)) {
+          replace = {start: e.pos, end: pos, type: __acorn.tokTypes.string, value: this$1.input.slice(e.pos + 1, pos)};
+        } else if (/regular expr/i.test(msg)) {
+          var re = this$1.input.slice(e.pos, pos);
+          try { re = new RegExp(re); } catch (e) { /* ignore compilation error due to new syntax */ }
+          replace = {start: e.pos, end: pos, type: __acorn.tokTypes.regexp, value: re};
+        } else if (/template/.test(msg)) {
+          replace = {
+            start: e.pos,
+            end: pos,
+            type: __acorn.tokTypes.template,
+            value: this$1.input.slice(e.pos, pos)
+          };
+        } else {
+          replace = false;
+        }
+      } else if (/invalid (unicode|regexp|number)|expecting unicode|octal literal|is reserved|directly after number|expected number in radix/i.test(msg)) {
+        while (pos < this.input.length && !isSpace(this.input.charCodeAt(pos))) { ++pos; }
+      } else if (/character escape|expected hexadecimal/i.test(msg)) {
+        while (pos < this.input.length) {
+          var ch = this$1.input.charCodeAt(pos++);
+          if (ch === 34 || ch === 39 || __acorn.isNewLine(ch)) { break }
+        }
+      } else if (/unexpected character/i.test(msg)) {
+        pos++;
+        replace = false;
+      } else if (/regular expression/i.test(msg)) {
+        replace = true;
+      } else {
+        throw e
+      }
+      this$1.resetTo(pos);
+      if (replace === true) { replace = {start: pos, end: pos, type: __acorn.tokTypes.name, value: "✖"}; }
+      if (replace) {
+        if (this$1.options.locations)
+          { replace.loc = new __acorn.SourceLocation(
+            this$1.toks,
+            __acorn.getLineInfo(this$1.input, replace.start),
+            __acorn.getLineInfo(this$1.input, replace.end)); }
+        return replace
+      }
+    }
+  }
+};
+
+lp.resetTo = function(pos) {
+  var this$1 = this;
+
+  this.toks.pos = pos;
+  var ch = this.input.charAt(pos - 1);
+  this.toks.exprAllowed = !ch || /[[{(,;:?/*=+\-~!|&%^<>]/.test(ch) ||
+    /[enwfd]/.test(ch) &&
+    /\b(keywords|case|else|return|throw|new|in|(instance|type)of|delete|void)$/.test(this.input.slice(pos - 10, pos));
+
+  if (this.options.locations) {
+    this.toks.curLine = 1;
+    this.toks.lineStart = __acorn.lineBreakG.lastIndex = 0;
+    var match;
+    while ((match = __acorn.lineBreakG.exec(this.input)) && match.index < pos) {
+      ++this$1.toks.curLine;
+      this$1.toks.lineStart = match.index + match[0].length;
+    }
+  }
+};
+
+lp.lookAhead = function(n) {
+  var this$1 = this;
+
+  while (n > this.ahead.length)
+    { this$1.ahead.push(this$1.readToken()); }
+  return this.ahead[n - 1]
+};
+
+function isDummy(node) { return node.name == "✖" }
+
+var lp$1 = LooseParser.prototype;
+
+lp$1.parseTopLevel = function() {
+  var this$1 = this;
+
+  var node = this.startNodeAt(this.options.locations ? [0, __acorn.getLineInfo(this.input, 0)] : 0);
+  node.body = [];
+  while (this.tok.type !== __acorn.tokTypes.eof) { node.body.push(this$1.parseStatement()); }
+  this.toks.adaptDirectivePrologue(node.body);
+  this.last = this.tok;
+  if (this.options.ecmaVersion >= 6) {
+    node.sourceType = this.options.sourceType;
+  }
+  return this.finishNode(node, "Program")
+};
+
+lp$1.parseStatement = function() {
+  var this$1 = this;
+
+  var starttype = this.tok.type, node = this.startNode(), kind;
+
+  if (this.toks.isLet()) {
+    starttype = __acorn.tokTypes._var;
+    kind = "let";
+  }
+
+  switch (starttype) {
+  case __acorn.tokTypes._break: case __acorn.tokTypes._continue:
+    this.next();
+    var isBreak = starttype === __acorn.tokTypes._break;
+    if (this.semicolon() || this.canInsertSemicolon()) {
+      node.label = null;
+    } else {
+      node.label = this.tok.type === __acorn.tokTypes.name ? this.parseIdent() : null;
+      this.semicolon();
+    }
+    return this.finishNode(node, isBreak ? "BreakStatement" : "ContinueStatement")
+
+  case __acorn.tokTypes._debugger:
+    this.next();
+    this.semicolon();
+    return this.finishNode(node, "DebuggerStatement")
+
+  case __acorn.tokTypes._do:
+    this.next();
+    node.body = this.parseStatement();
+    node.test = this.eat(__acorn.tokTypes._while) ? this.parseParenExpression() : this.dummyIdent();
+    this.semicolon();
+    return this.finishNode(node, "DoWhileStatement")
+
+  case __acorn.tokTypes._for:
+    this.next();
+    this.pushCx();
+    this.expect(__acorn.tokTypes.parenL);
+    if (this.tok.type === __acorn.tokTypes.semi) { return this.parseFor(node, null) }
+    var isLet = this.toks.isLet();
+    if (isLet || this.tok.type === __acorn.tokTypes._var || this.tok.type === __acorn.tokTypes._const) {
+      var init$1 = this.parseVar(true, isLet ? "let" : this.tok.value);
+      if (init$1.declarations.length === 1 && (this.tok.type === __acorn.tokTypes._in || this.isContextual("of"))) {
+        return this.parseForIn(node, init$1)
+      }
+      return this.parseFor(node, init$1)
+    }
+    var init = this.parseExpression(true);
+    if (this.tok.type === __acorn.tokTypes._in || this.isContextual("of"))
+      { return this.parseForIn(node, this.toAssignable(init)) }
+    return this.parseFor(node, init)
+
+  case __acorn.tokTypes._function:
+    this.next();
+    return this.parseFunction(node, true)
+
+  case __acorn.tokTypes._if:
+    this.next();
+    node.test = this.parseParenExpression();
+    node.consequent = this.parseStatement();
+    node.alternate = this.eat(__acorn.tokTypes._else) ? this.parseStatement() : null;
+    return this.finishNode(node, "IfStatement")
+
+  case __acorn.tokTypes._return:
+    this.next();
+    if (this.eat(__acorn.tokTypes.semi) || this.canInsertSemicolon()) { node.argument = null; }
+    else { node.argument = this.parseExpression(); this.semicolon(); }
+    return this.finishNode(node, "ReturnStatement")
+
+  case __acorn.tokTypes._switch:
+    var blockIndent = this.curIndent, line = this.curLineStart;
+    this.next();
+    node.discriminant = this.parseParenExpression();
+    node.cases = [];
+    this.pushCx();
+    this.expect(__acorn.tokTypes.braceL);
+
+    var cur;
+    while (!this.closes(__acorn.tokTypes.braceR, blockIndent, line, true)) {
+      if (this$1.tok.type === __acorn.tokTypes._case || this$1.tok.type === __acorn.tokTypes._default) {
+        var isCase = this$1.tok.type === __acorn.tokTypes._case;
+        if (cur) { this$1.finishNode(cur, "SwitchCase"); }
+        node.cases.push(cur = this$1.startNode());
+        cur.consequent = [];
+        this$1.next();
+        if (isCase) { cur.test = this$1.parseExpression(); }
+        else { cur.test = null; }
+        this$1.expect(__acorn.tokTypes.colon);
+      } else {
+        if (!cur) {
+          node.cases.push(cur = this$1.startNode());
+          cur.consequent = [];
+          cur.test = null;
+        }
+        cur.consequent.push(this$1.parseStatement());
+      }
+    }
+    if (cur) { this.finishNode(cur, "SwitchCase"); }
+    this.popCx();
+    this.eat(__acorn.tokTypes.braceR);
+    return this.finishNode(node, "SwitchStatement")
+
+  case __acorn.tokTypes._throw:
+    this.next();
+    node.argument = this.parseExpression();
+    this.semicolon();
+    return this.finishNode(node, "ThrowStatement")
+
+  case __acorn.tokTypes._try:
+    this.next();
+    node.block = this.parseBlock();
+    node.handler = null;
+    if (this.tok.type === __acorn.tokTypes._catch) {
+      var clause = this.startNode();
+      this.next();
+      this.expect(__acorn.tokTypes.parenL);
+      clause.param = this.toAssignable(this.parseExprAtom(), true);
+      this.expect(__acorn.tokTypes.parenR);
+      clause.body = this.parseBlock();
+      node.handler = this.finishNode(clause, "CatchClause");
+    }
+    node.finalizer = this.eat(__acorn.tokTypes._finally) ? this.parseBlock() : null;
+    if (!node.handler && !node.finalizer) { return node.block }
+    return this.finishNode(node, "TryStatement")
+
+  case __acorn.tokTypes._var:
+  case __acorn.tokTypes._const:
+    return this.parseVar(false, kind || this.tok.value)
+
+  case __acorn.tokTypes._while:
+    this.next();
+    node.test = this.parseParenExpression();
+    node.body = this.parseStatement();
+    return this.finishNode(node, "WhileStatement")
+
+  case __acorn.tokTypes._with:
+    this.next();
+    node.object = this.parseParenExpression();
+    node.body = this.parseStatement();
+    return this.finishNode(node, "WithStatement")
+
+  case __acorn.tokTypes.braceL:
+    return this.parseBlock()
+
+  case __acorn.tokTypes.semi:
+    this.next();
+    return this.finishNode(node, "EmptyStatement")
+
+  case __acorn.tokTypes._class:
+    return this.parseClass(true)
+
+  case __acorn.tokTypes._import:
+    return this.parseImport()
+
+  case __acorn.tokTypes._export:
+    return this.parseExport()
+
+  default:
+    if (this.toks.isAsyncFunction()) {
+      this.next();
+      this.next();
+      return this.parseFunction(node, true, true)
+    }
+    var expr = this.parseExpression();
+    if (isDummy(expr)) {
+      this.next();
+      if (this.tok.type === __acorn.tokTypes.eof) { return this.finishNode(node, "EmptyStatement") }
+      return this.parseStatement()
+    } else if (starttype === __acorn.tokTypes.name && expr.type === "Identifier" && this.eat(__acorn.tokTypes.colon)) {
+      node.body = this.parseStatement();
+      node.label = expr;
+      return this.finishNode(node, "LabeledStatement")
+    } else {
+      node.expression = expr;
+      this.semicolon();
+      return this.finishNode(node, "ExpressionStatement")
+    }
+  }
+};
+
+lp$1.parseBlock = function() {
+  var this$1 = this;
+
+  var node = this.startNode();
+  this.pushCx();
+  this.expect(__acorn.tokTypes.braceL);
+  var blockIndent = this.curIndent, line = this.curLineStart;
+  node.body = [];
+  while (!this.closes(__acorn.tokTypes.braceR, blockIndent, line, true))
+    { node.body.push(this$1.parseStatement()); }
+  this.popCx();
+  this.eat(__acorn.tokTypes.braceR);
+  return this.finishNode(node, "BlockStatement")
+};
+
+lp$1.parseFor = function(node, init) {
+  node.init = init;
+  node.test = node.update = null;
+  if (this.eat(__acorn.tokTypes.semi) && this.tok.type !== __acorn.tokTypes.semi) { node.test = this.parseExpression(); }
+  if (this.eat(__acorn.tokTypes.semi) && this.tok.type !== __acorn.tokTypes.parenR) { node.update = this.parseExpression(); }
+  this.popCx();
+  this.expect(__acorn.tokTypes.parenR);
+  node.body = this.parseStatement();
+  return this.finishNode(node, "ForStatement")
+};
+
+lp$1.parseForIn = function(node, init) {
+  var type = this.tok.type === __acorn.tokTypes._in ? "ForInStatement" : "ForOfStatement";
+  this.next();
+  node.left = init;
+  node.right = this.parseExpression();
+  this.popCx();
+  this.expect(__acorn.tokTypes.parenR);
+  node.body = this.parseStatement();
+  return this.finishNode(node, type)
+};
+
+lp$1.parseVar = function(noIn, kind) {
+  var this$1 = this;
+
+  var node = this.startNode();
+  node.kind = kind;
+  this.next();
+  node.declarations = [];
+  do {
+    var decl = this$1.startNode();
+    decl.id = this$1.options.ecmaVersion >= 6 ? this$1.toAssignable(this$1.parseExprAtom(), true) : this$1.parseIdent();
+    decl.init = this$1.eat(__acorn.tokTypes.eq) ? this$1.parseMaybeAssign(noIn) : null;
+    node.declarations.push(this$1.finishNode(decl, "VariableDeclarator"));
+  } while (this.eat(__acorn.tokTypes.comma))
+  if (!node.declarations.length) {
+    var decl$1 = this.startNode();
+    decl$1.id = this.dummyIdent();
+    node.declarations.push(this.finishNode(decl$1, "VariableDeclarator"));
+  }
+  if (!noIn) { this.semicolon(); }
+  return this.finishNode(node, "VariableDeclaration")
+};
+
+lp$1.parseClass = function(isStatement) {
+  var this$1 = this;
+
+  var node = this.startNode();
+  this.next();
+  if (this.tok.type === __acorn.tokTypes.name) { node.id = this.parseIdent(); }
+  else if (isStatement === true) { node.id = this.dummyIdent(); }
+  else { node.id = null; }
+  node.superClass = this.eat(__acorn.tokTypes._extends) ? this.parseExpression() : null;
+  node.body = this.startNode();
+  node.body.body = [];
+  this.pushCx();
+  var indent = this.curIndent + 1, line = this.curLineStart;
+  this.eat(__acorn.tokTypes.braceL);
+  if (this.curIndent + 1 < indent) { indent = this.curIndent; line = this.curLineStart; }
+  while (!this.closes(__acorn.tokTypes.braceR, indent, line)) {
+    if (this$1.semicolon()) { continue }
+    var method = this$1.startNode(), isGenerator = (void 0), isAsync = (void 0);
+    if (this$1.options.ecmaVersion >= 6) {
+      method.static = false;
+      isGenerator = this$1.eat(__acorn.tokTypes.star);
+    }
+    this$1.parsePropertyName(method);
+    if (isDummy(method.key)) { if (isDummy(this$1.parseMaybeAssign())) { this$1.next(); } this$1.eat(__acorn.tokTypes.comma); continue }
+    if (method.key.type === "Identifier" && !method.computed && method.key.name === "static" &&
+        (this$1.tok.type != __acorn.tokTypes.parenL && this$1.tok.type != __acorn.tokTypes.braceL)) {
+      method.static = true;
+      isGenerator = this$1.eat(__acorn.tokTypes.star);
+      this$1.parsePropertyName(method);
+    } else {
+      method.static = false;
+    }
+    if (!method.computed &&
+        method.key.type === "Identifier" && method.key.name === "async" && this$1.tok.type !== __acorn.tokTypes.parenL &&
+        !this$1.canInsertSemicolon()) {
+      this$1.parsePropertyName(method);
+      isAsync = true;
+    } else {
+      isAsync = false;
+    }
+    if (this$1.options.ecmaVersion >= 5 && method.key.type === "Identifier" &&
+        !method.computed && (method.key.name === "get" || method.key.name === "set") &&
+        this$1.tok.type !== __acorn.tokTypes.parenL && this$1.tok.type !== __acorn.tokTypes.braceL) {
+      method.kind = method.key.name;
+      this$1.parsePropertyName(method);
+      method.value = this$1.parseMethod(false);
+    } else {
+      if (!method.computed && !method.static && !isGenerator && !isAsync && (
+        method.key.type === "Identifier" && method.key.name === "constructor" ||
+          method.key.type === "Literal" && method.key.value === "constructor")) {
+        method.kind = "constructor";
+      } else {
+        method.kind = "method";
+      }
+      method.value = this$1.parseMethod(isGenerator, isAsync);
+    }
+    node.body.body.push(this$1.finishNode(method, "MethodDefinition"));
+  }
+  this.popCx();
+  if (!this.eat(__acorn.tokTypes.braceR)) {
+    // If there is no closing brace, make the node span to the start
+    // of the next token (this is useful for Tern)
+    this.last.end = this.tok.start;
+    if (this.options.locations) { this.last.loc.end = this.tok.loc.start; }
+  }
+  this.semicolon();
+  this.finishNode(node.body, "ClassBody");
+  return this.finishNode(node, isStatement ? "ClassDeclaration" : "ClassExpression")
+};
+
+lp$1.parseFunction = function(node, isStatement, isAsync) {
+  var oldInAsync = this.inAsync;
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 6) {
+    node.generator = this.eat(__acorn.tokTypes.star);
+  }
+  if (this.options.ecmaVersion >= 8) {
+    node.async = !!isAsync;
+  }
+  if (this.tok.type === __acorn.tokTypes.name) { node.id = this.parseIdent(); }
+  else if (isStatement === true) { node.id = this.dummyIdent(); }
+  this.inAsync = node.async;
+  node.params = this.parseFunctionParams();
+  node.body = this.parseBlock();
+  this.toks.adaptDirectivePrologue(node.body.body);
+  this.inAsync = oldInAsync;
+  return this.finishNode(node, isStatement ? "FunctionDeclaration" : "FunctionExpression")
+};
+
+lp$1.parseExport = function() {
+  var node = this.startNode();
+  this.next();
+  if (this.eat(__acorn.tokTypes.star)) {
+    node.source = this.eatContextual("from") ? this.parseExprAtom() : this.dummyString();
+    return this.finishNode(node, "ExportAllDeclaration")
+  }
+  if (this.eat(__acorn.tokTypes._default)) {
+    // export default (function foo() {}) // This is FunctionExpression.
+    var isAsync;
+    if (this.tok.type === __acorn.tokTypes._function || (isAsync = this.toks.isAsyncFunction())) {
+      var fNode = this.startNode();
+      this.next();
+      if (isAsync) { this.next(); }
+      node.declaration = this.parseFunction(fNode, "nullableID", isAsync);
+    } else if (this.tok.type === __acorn.tokTypes._class) {
+      node.declaration = this.parseClass("nullableID");
+    } else {
+      node.declaration = this.parseMaybeAssign();
+      this.semicolon();
+    }
+    return this.finishNode(node, "ExportDefaultDeclaration")
+  }
+  if (this.tok.type.keyword || this.toks.isLet() || this.toks.isAsyncFunction()) {
+    node.declaration = this.parseStatement();
+    node.specifiers = [];
+    node.source = null;
+  } else {
+    node.declaration = null;
+    node.specifiers = this.parseExportSpecifierList();
+    node.source = this.eatContextual("from") ? this.parseExprAtom() : null;
+    this.semicolon();
+  }
+  return this.finishNode(node, "ExportNamedDeclaration")
+};
+
+lp$1.parseImport = function() {
+  var node = this.startNode();
+  this.next();
+  if (this.tok.type === __acorn.tokTypes.string) {
+    node.specifiers = [];
+    node.source = this.parseExprAtom();
+  } else {
+    var elt;
+    if (this.tok.type === __acorn.tokTypes.name && this.tok.value !== "from") {
+      elt = this.startNode();
+      elt.local = this.parseIdent();
+      this.finishNode(elt, "ImportDefaultSpecifier");
+      this.eat(__acorn.tokTypes.comma);
+    }
+    node.specifiers = this.parseImportSpecifierList();
+    node.source = this.eatContextual("from") && this.tok.type == __acorn.tokTypes.string ? this.parseExprAtom() : this.dummyString();
+    if (elt) { node.specifiers.unshift(elt); }
+  }
+  this.semicolon();
+  return this.finishNode(node, "ImportDeclaration")
+};
+
+lp$1.parseImportSpecifierList = function() {
+  var this$1 = this;
+
+  var elts = [];
+  if (this.tok.type === __acorn.tokTypes.star) {
+    var elt = this.startNode();
+    this.next();
+    elt.local = this.eatContextual("as") ? this.parseIdent() : this.dummyIdent();
+    elts.push(this.finishNode(elt, "ImportNamespaceSpecifier"));
+  } else {
+    var indent = this.curIndent, line = this.curLineStart, continuedLine = this.nextLineStart;
+    this.pushCx();
+    this.eat(__acorn.tokTypes.braceL);
+    if (this.curLineStart > continuedLine) { continuedLine = this.curLineStart; }
+    while (!this.closes(__acorn.tokTypes.braceR, indent + (this.curLineStart <= continuedLine ? 1 : 0), line)) {
+      var elt$1 = this$1.startNode();
+      if (this$1.eat(__acorn.tokTypes.star)) {
+        elt$1.local = this$1.eatContextual("as") ? this$1.parseIdent() : this$1.dummyIdent();
+        this$1.finishNode(elt$1, "ImportNamespaceSpecifier");
+      } else {
+        if (this$1.isContextual("from")) { break }
+        elt$1.imported = this$1.parseIdent();
+        if (isDummy(elt$1.imported)) { break }
+        elt$1.local = this$1.eatContextual("as") ? this$1.parseIdent() : elt$1.imported;
+        this$1.finishNode(elt$1, "ImportSpecifier");
+      }
+      elts.push(elt$1);
+      this$1.eat(__acorn.tokTypes.comma);
+    }
+    this.eat(__acorn.tokTypes.braceR);
+    this.popCx();
+  }
+  return elts
+};
+
+lp$1.parseExportSpecifierList = function() {
+  var this$1 = this;
+
+  var elts = [];
+  var indent = this.curIndent, line = this.curLineStart, continuedLine = this.nextLineStart;
+  this.pushCx();
+  this.eat(__acorn.tokTypes.braceL);
+  if (this.curLineStart > continuedLine) { continuedLine = this.curLineStart; }
+  while (!this.closes(__acorn.tokTypes.braceR, indent + (this.curLineStart <= continuedLine ? 1 : 0), line)) {
+    if (this$1.isContextual("from")) { break }
+    var elt = this$1.startNode();
+    elt.local = this$1.parseIdent();
+    if (isDummy(elt.local)) { break }
+    elt.exported = this$1.eatContextual("as") ? this$1.parseIdent() : elt.local;
+    this$1.finishNode(elt, "ExportSpecifier");
+    elts.push(elt);
+    this$1.eat(__acorn.tokTypes.comma);
+  }
+  this.eat(__acorn.tokTypes.braceR);
+  this.popCx();
+  return elts
+};
+
+var lp$2 = LooseParser.prototype;
+
+lp$2.checkLVal = function(expr) {
+  if (!expr) { return expr }
+  switch (expr.type) {
+  case "Identifier":
+  case "MemberExpression":
+    return expr
+
+  case "ParenthesizedExpression":
+    expr.expression = this.checkLVal(expr.expression);
+    return expr
+
+  default:
+    return this.dummyIdent()
+  }
+};
+
+lp$2.parseExpression = function(noIn) {
+  var this$1 = this;
+
+  var start = this.storeCurrentPos();
+  var expr = this.parseMaybeAssign(noIn);
+  if (this.tok.type === __acorn.tokTypes.comma) {
+    var node = this.startNodeAt(start);
+    node.expressions = [expr];
+    while (this.eat(__acorn.tokTypes.comma)) { node.expressions.push(this$1.parseMaybeAssign(noIn)); }
+    return this.finishNode(node, "SequenceExpression")
+  }
+  return expr
+};
+
+lp$2.parseParenExpression = function() {
+  this.pushCx();
+  this.expect(__acorn.tokTypes.parenL);
+  var val = this.parseExpression();
+  this.popCx();
+  this.expect(__acorn.tokTypes.parenR);
+  return val
+};
+
+lp$2.parseMaybeAssign = function(noIn) {
+  if (this.toks.isContextual("yield")) {
+    var node = this.startNode();
+    this.next();
+    if (this.semicolon() || this.canInsertSemicolon() || (this.tok.type != __acorn.tokTypes.star && !this.tok.type.startsExpr)) {
+      node.delegate = false;
+      node.argument = null;
+    } else {
+      node.delegate = this.eat(__acorn.tokTypes.star);
+      node.argument = this.parseMaybeAssign();
+    }
+    return this.finishNode(node, "YieldExpression")
+  }
+
+  var start = this.storeCurrentPos();
+  var left = this.parseMaybeConditional(noIn);
+  if (this.tok.type.isAssign) {
+    var node$1 = this.startNodeAt(start);
+    node$1.operator = this.tok.value;
+    node$1.left = this.tok.type === __acorn.tokTypes.eq ? this.toAssignable(left) : this.checkLVal(left);
+    this.next();
+    node$1.right = this.parseMaybeAssign(noIn);
+    return this.finishNode(node$1, "AssignmentExpression")
+  }
+  return left
+};
+
+lp$2.parseMaybeConditional = function(noIn) {
+  var start = this.storeCurrentPos();
+  var expr = this.parseExprOps(noIn);
+  if (this.eat(__acorn.tokTypes.question)) {
+    var node = this.startNodeAt(start);
+    node.test = expr;
+    node.consequent = this.parseMaybeAssign();
+    node.alternate = this.expect(__acorn.tokTypes.colon) ? this.parseMaybeAssign(noIn) : this.dummyIdent();
+    return this.finishNode(node, "ConditionalExpression")
+  }
+  return expr
+};
+
+lp$2.parseExprOps = function(noIn) {
+  var start = this.storeCurrentPos();
+  var indent = this.curIndent, line = this.curLineStart;
+  return this.parseExprOp(this.parseMaybeUnary(false), start, -1, noIn, indent, line)
+};
+
+lp$2.parseExprOp = function(left, start, minPrec, noIn, indent, line) {
+  if (this.curLineStart != line && this.curIndent < indent && this.tokenStartsLine()) { return left }
+  var prec = this.tok.type.binop;
+  if (prec != null && (!noIn || this.tok.type !== __acorn.tokTypes._in)) {
+    if (prec > minPrec) {
+      var node = this.startNodeAt(start);
+      node.left = left;
+      node.operator = this.tok.value;
+      this.next();
+      if (this.curLineStart != line && this.curIndent < indent && this.tokenStartsLine()) {
+        node.right = this.dummyIdent();
+      } else {
+        var rightStart = this.storeCurrentPos();
+        node.right = this.parseExprOp(this.parseMaybeUnary(false), rightStart, prec, noIn, indent, line);
+      }
+      this.finishNode(node, /&&|\|\|/.test(node.operator) ? "LogicalExpression" : "BinaryExpression");
+      return this.parseExprOp(node, start, minPrec, noIn, indent, line)
+    }
+  }
+  return left
+};
+
+lp$2.parseMaybeUnary = function(sawUnary) {
+  var this$1 = this;
+
+  var start = this.storeCurrentPos(), expr;
+  if (this.options.ecmaVersion >= 8 && this.inAsync && this.toks.isContextual("await")) {
+    expr = this.parseAwait();
+    sawUnary = true;
+  } else if (this.tok.type.prefix) {
+    var node = this.startNode(), update = this.tok.type === __acorn.tokTypes.incDec;
+    if (!update) { sawUnary = true; }
+    node.operator = this.tok.value;
+    node.prefix = true;
+    this.next();
+    node.argument = this.parseMaybeUnary(true);
+    if (update) { node.argument = this.checkLVal(node.argument); }
+    expr = this.finishNode(node, update ? "UpdateExpression" : "UnaryExpression");
+  } else if (this.tok.type === __acorn.tokTypes.ellipsis) {
+    var node$1 = this.startNode();
+    this.next();
+    node$1.argument = this.parseMaybeUnary(sawUnary);
+    expr = this.finishNode(node$1, "SpreadElement");
+  } else {
+    expr = this.parseExprSubscripts();
+    while (this.tok.type.postfix && !this.canInsertSemicolon()) {
+      var node$2 = this$1.startNodeAt(start);
+      node$2.operator = this$1.tok.value;
+      node$2.prefix = false;
+      node$2.argument = this$1.checkLVal(expr);
+      this$1.next();
+      expr = this$1.finishNode(node$2, "UpdateExpression");
+    }
+  }
+
+  if (!sawUnary && this.eat(__acorn.tokTypes.starstar)) {
+    var node$3 = this.startNodeAt(start);
+    node$3.operator = "**";
+    node$3.left = expr;
+    node$3.right = this.parseMaybeUnary(false);
+    return this.finishNode(node$3, "BinaryExpression")
+  }
+
+  return expr
+};
+
+lp$2.parseExprSubscripts = function() {
+  var start = this.storeCurrentPos();
+  return this.parseSubscripts(this.parseExprAtom(), start, false, this.curIndent, this.curLineStart)
+};
+
+lp$2.parseSubscripts = function(base, start, noCalls, startIndent, line) {
+  var this$1 = this;
+
+  for (;;) {
+    if (this$1.curLineStart != line && this$1.curIndent <= startIndent && this$1.tokenStartsLine()) {
+      if (this$1.tok.type == __acorn.tokTypes.dot && this$1.curIndent == startIndent)
+        { --startIndent; }
+      else
+        { return base }
+    }
+
+    var maybeAsyncArrow = base.type === "Identifier" && base.name === "async" && !this$1.canInsertSemicolon();
+
+    if (this$1.eat(__acorn.tokTypes.dot)) {
+      var node = this$1.startNodeAt(start);
+      node.object = base;
+      if (this$1.curLineStart != line && this$1.curIndent <= startIndent && this$1.tokenStartsLine())
+        { node.property = this$1.dummyIdent(); }
+      else
+        { node.property = this$1.parsePropertyAccessor() || this$1.dummyIdent(); }
+      node.computed = false;
+      base = this$1.finishNode(node, "MemberExpression");
+    } else if (this$1.tok.type == __acorn.tokTypes.bracketL) {
+      this$1.pushCx();
+      this$1.next();
+      var node$1 = this$1.startNodeAt(start);
+      node$1.object = base;
+      node$1.property = this$1.parseExpression();
+      node$1.computed = true;
+      this$1.popCx();
+      this$1.expect(__acorn.tokTypes.bracketR);
+      base = this$1.finishNode(node$1, "MemberExpression");
+    } else if (!noCalls && this$1.tok.type == __acorn.tokTypes.parenL) {
+      var exprList = this$1.parseExprList(__acorn.tokTypes.parenR);
+      if (maybeAsyncArrow && this$1.eat(__acorn.tokTypes.arrow))
+        { return this$1.parseArrowExpression(this$1.startNodeAt(start), exprList, true) }
+      var node$2 = this$1.startNodeAt(start);
+      node$2.callee = base;
+      node$2.arguments = exprList;
+      base = this$1.finishNode(node$2, "CallExpression");
+    } else if (this$1.tok.type == __acorn.tokTypes.backQuote) {
+      var node$3 = this$1.startNodeAt(start);
+      node$3.tag = base;
+      node$3.quasi = this$1.parseTemplate();
+      base = this$1.finishNode(node$3, "TaggedTemplateExpression");
+    } else {
+      return base
+    }
+  }
+};
+
+lp$2.parseExprAtom = function() {
+  var node;
+  switch (this.tok.type) {
+  case __acorn.tokTypes._this:
+  case __acorn.tokTypes._super:
+    var type = this.tok.type === __acorn.tokTypes._this ? "ThisExpression" : "Super";
+    node = this.startNode();
+    this.next();
+    return this.finishNode(node, type)
+
+  case __acorn.tokTypes.name:
+    var start = this.storeCurrentPos();
+    var id = this.parseIdent();
+    var isAsync = false;
+    if (id.name === "async" && !this.canInsertSemicolon()) {
+      if (this.eat(__acorn.tokTypes._function))
+        { return this.parseFunction(this.startNodeAt(start), false, true) }
+      if (this.tok.type === __acorn.tokTypes.name) {
+        id = this.parseIdent();
+        isAsync = true;
+      }
+    }
+    return this.eat(__acorn.tokTypes.arrow) ? this.parseArrowExpression(this.startNodeAt(start), [id], isAsync) : id
+
+  case __acorn.tokTypes.regexp:
+    node = this.startNode();
+    var val = this.tok.value;
+    node.regex = {pattern: val.pattern, flags: val.flags};
+    node.value = val.value;
+    node.raw = this.input.slice(this.tok.start, this.tok.end);
+    this.next();
+    return this.finishNode(node, "Literal")
+
+  case __acorn.tokTypes.num: case __acorn.tokTypes.string:
+    node = this.startNode();
+    node.value = this.tok.value;
+    node.raw = this.input.slice(this.tok.start, this.tok.end);
+    this.next();
+    return this.finishNode(node, "Literal")
+
+  case __acorn.tokTypes._null: case __acorn.tokTypes._true: case __acorn.tokTypes._false:
+    node = this.startNode();
+    node.value = this.tok.type === __acorn.tokTypes._null ? null : this.tok.type === __acorn.tokTypes._true;
+    node.raw = this.tok.type.keyword;
+    this.next();
+    return this.finishNode(node, "Literal")
+
+  case __acorn.tokTypes.parenL:
+    var parenStart = this.storeCurrentPos();
+    this.next();
+    var inner = this.parseExpression();
+    this.expect(__acorn.tokTypes.parenR);
+    if (this.eat(__acorn.tokTypes.arrow)) {
+      // (a,)=>a // SequenceExpression makes dummy in the last hole. Drop the dummy.
+      var params = inner.expressions || [inner];
+      if (params.length && isDummy(params[params.length - 1]))
+        { params.pop(); }
+      return this.parseArrowExpression(this.startNodeAt(parenStart), params)
+    }
+    if (this.options.preserveParens) {
+      var par = this.startNodeAt(parenStart);
+      par.expression = inner;
+      inner = this.finishNode(par, "ParenthesizedExpression");
+    }
+    return inner
+
+  case __acorn.tokTypes.bracketL:
+    node = this.startNode();
+    node.elements = this.parseExprList(__acorn.tokTypes.bracketR, true);
+    return this.finishNode(node, "ArrayExpression")
+
+  case __acorn.tokTypes.braceL:
+    return this.parseObj()
+
+  case __acorn.tokTypes._class:
+    return this.parseClass(false)
+
+  case __acorn.tokTypes._function:
+    node = this.startNode();
+    this.next();
+    return this.parseFunction(node, false)
+
+  case __acorn.tokTypes._new:
+    return this.parseNew()
+
+  case __acorn.tokTypes.backQuote:
+    return this.parseTemplate()
+
+  default:
+    return this.dummyIdent()
+  }
+};
+
+lp$2.parseNew = function() {
+  var node = this.startNode(), startIndent = this.curIndent, line = this.curLineStart;
+  var meta = this.parseIdent(true);
+  if (this.options.ecmaVersion >= 6 && this.eat(__acorn.tokTypes.dot)) {
+    node.meta = meta;
+    node.property = this.parseIdent(true);
+    return this.finishNode(node, "MetaProperty")
+  }
+  var start = this.storeCurrentPos();
+  node.callee = this.parseSubscripts(this.parseExprAtom(), start, true, startIndent, line);
+  if (this.tok.type == __acorn.tokTypes.parenL) {
+    node.arguments = this.parseExprList(__acorn.tokTypes.parenR);
+  } else {
+    node.arguments = [];
+  }
+  return this.finishNode(node, "NewExpression")
+};
+
+lp$2.parseTemplateElement = function() {
+  var elem = this.startNode();
+
+  // The loose parser accepts invalid unicode escapes even in untagged templates.
+  if (this.tok.type === __acorn.tokTypes.invalidTemplate) {
+    elem.value = {
+      raw: this.tok.value,
+      cooked: null
+    };
+  } else {
+    elem.value = {
+      raw: this.input.slice(this.tok.start, this.tok.end).replace(/\r\n?/g, "\n"),
+      cooked: this.tok.value
+    };
+  }
+  this.next();
+  elem.tail = this.tok.type === __acorn.tokTypes.backQuote;
+  return this.finishNode(elem, "TemplateElement")
+};
+
+lp$2.parseTemplate = function() {
+  var this$1 = this;
+
+  var node = this.startNode();
+  this.next();
+  node.expressions = [];
+  var curElt = this.parseTemplateElement();
+  node.quasis = [curElt];
+  while (!curElt.tail) {
+    this$1.next();
+    node.expressions.push(this$1.parseExpression());
+    if (this$1.expect(__acorn.tokTypes.braceR)) {
+      curElt = this$1.parseTemplateElement();
+    } else {
+      curElt = this$1.startNode();
+      curElt.value = {cooked: "", raw: ""};
+      curElt.tail = true;
+      this$1.finishNode(curElt, "TemplateElement");
+    }
+    node.quasis.push(curElt);
+  }
+  this.expect(__acorn.tokTypes.backQuote);
+  return this.finishNode(node, "TemplateLiteral")
+};
+
+lp$2.parseObj = function() {
+  var this$1 = this;
+
+  var node = this.startNode();
+  node.properties = [];
+  this.pushCx();
+  var indent = this.curIndent + 1, line = this.curLineStart;
+  this.eat(__acorn.tokTypes.braceL);
+  if (this.curIndent + 1 < indent) { indent = this.curIndent; line = this.curLineStart; }
+  while (!this.closes(__acorn.tokTypes.braceR, indent, line)) {
+    var prop = this$1.startNode(), isGenerator = (void 0), isAsync = (void 0), start = (void 0);
+    if (this$1.options.ecmaVersion >= 6) {
+      start = this$1.storeCurrentPos();
+      prop.method = false;
+      prop.shorthand = false;
+      isGenerator = this$1.eat(__acorn.tokTypes.star);
+    }
+    this$1.parsePropertyName(prop);
+    if (this$1.toks.isAsyncProp(prop)) {
+      this$1.parsePropertyName(prop);
+      isAsync = true;
+    } else {
+      isAsync = false;
+    }
+    if (isDummy(prop.key)) { if (isDummy(this$1.parseMaybeAssign())) { this$1.next(); } this$1.eat(__acorn.tokTypes.comma); continue }
+    if (this$1.eat(__acorn.tokTypes.colon)) {
+      prop.kind = "init";
+      prop.value = this$1.parseMaybeAssign();
+    } else if (this$1.options.ecmaVersion >= 6 && (this$1.tok.type === __acorn.tokTypes.parenL || this$1.tok.type === __acorn.tokTypes.braceL)) {
+      prop.kind = "init";
+      prop.method = true;
+      prop.value = this$1.parseMethod(isGenerator, isAsync);
+    } else if (this$1.options.ecmaVersion >= 5 && prop.key.type === "Identifier" &&
+               !prop.computed && (prop.key.name === "get" || prop.key.name === "set") &&
+               (this$1.tok.type != __acorn.tokTypes.comma && this$1.tok.type != __acorn.tokTypes.braceR && this$1.tok.type != __acorn.tokTypes.eq)) {
+      prop.kind = prop.key.name;
+      this$1.parsePropertyName(prop);
+      prop.value = this$1.parseMethod(false);
+    } else {
+      prop.kind = "init";
+      if (this$1.options.ecmaVersion >= 6) {
+        if (this$1.eat(__acorn.tokTypes.eq)) {
+          var assign = this$1.startNodeAt(start);
+          assign.operator = "=";
+          assign.left = prop.key;
+          assign.right = this$1.parseMaybeAssign();
+          prop.value = this$1.finishNode(assign, "AssignmentExpression");
+        } else {
+          prop.value = prop.key;
+        }
+      } else {
+        prop.value = this$1.dummyIdent();
+      }
+      prop.shorthand = true;
+    }
+    node.properties.push(this$1.finishNode(prop, "Property"));
+    this$1.eat(__acorn.tokTypes.comma);
+  }
+  this.popCx();
+  if (!this.eat(__acorn.tokTypes.braceR)) {
+    // If there is no closing brace, make the node span to the start
+    // of the next token (this is useful for Tern)
+    this.last.end = this.tok.start;
+    if (this.options.locations) { this.last.loc.end = this.tok.loc.start; }
+  }
+  return this.finishNode(node, "ObjectExpression")
+};
+
+lp$2.parsePropertyName = function(prop) {
+  if (this.options.ecmaVersion >= 6) {
+    if (this.eat(__acorn.tokTypes.bracketL)) {
+      prop.computed = true;
+      prop.key = this.parseExpression();
+      this.expect(__acorn.tokTypes.bracketR);
+      return
+    } else {
+      prop.computed = false;
+    }
+  }
+  var key = (this.tok.type === __acorn.tokTypes.num || this.tok.type === __acorn.tokTypes.string) ? this.parseExprAtom() : this.parseIdent();
+  prop.key = key || this.dummyIdent();
+};
+
+lp$2.parsePropertyAccessor = function() {
+  if (this.tok.type === __acorn.tokTypes.name || this.tok.type.keyword) { return this.parseIdent() }
+};
+
+lp$2.parseIdent = function() {
+  var name = this.tok.type === __acorn.tokTypes.name ? this.tok.value : this.tok.type.keyword;
+  if (!name) { return this.dummyIdent() }
+  var node = this.startNode();
+  this.next();
+  node.name = name;
+  return this.finishNode(node, "Identifier")
+};
+
+lp$2.initFunction = function(node) {
+  node.id = null;
+  node.params = [];
+  if (this.options.ecmaVersion >= 6) {
+    node.generator = false;
+    node.expression = false;
+  }
+  if (this.options.ecmaVersion >= 8)
+    { node.async = false; }
+};
+
+// Convert existing expression atom to assignable pattern
+// if possible.
+
+lp$2.toAssignable = function(node, binding) {
+  var this$1 = this;
+
+  if (!node || node.type == "Identifier" || (node.type == "MemberExpression" && !binding)) {
+    // Okay
+  } else if (node.type == "ParenthesizedExpression") {
+    this.toAssignable(node.expression, binding);
+  } else if (this.options.ecmaVersion < 6) {
+    return this.dummyIdent()
+  } else if (node.type == "ObjectExpression") {
+    node.type = "ObjectPattern";
+    var props = node.properties;
+    for (var i = 0, list = props; i < list.length; i += 1)
+      {
+      var prop = list[i];
+
+      this$1.toAssignable(prop.value, binding);
+    }
+  } else if (node.type == "ArrayExpression") {
+    node.type = "ArrayPattern";
+    this.toAssignableList(node.elements, binding);
+  } else if (node.type == "SpreadElement") {
+    node.type = "RestElement";
+    this.toAssignable(node.argument, binding);
+  } else if (node.type == "AssignmentExpression") {
+    node.type = "AssignmentPattern";
+    delete node.operator;
+  } else {
+    return this.dummyIdent()
+  }
+  return node
+};
+
+lp$2.toAssignableList = function(exprList, binding) {
+  var this$1 = this;
+
+  for (var i = 0, list = exprList; i < list.length; i += 1)
+    {
+    var expr = list[i];
+
+    this$1.toAssignable(expr, binding);
+  }
+  return exprList
+};
+
+lp$2.parseFunctionParams = function(params) {
+  params = this.parseExprList(__acorn.tokTypes.parenR);
+  return this.toAssignableList(params, true)
+};
+
+lp$2.parseMethod = function(isGenerator, isAsync) {
+  var node = this.startNode(), oldInAsync = this.inAsync;
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 6)
+    { node.generator = !!isGenerator; }
+  if (this.options.ecmaVersion >= 8)
+    { node.async = !!isAsync; }
+  this.inAsync = node.async;
+  node.params = this.parseFunctionParams();
+  node.body = this.parseBlock();
+  this.toks.adaptDirectivePrologue(node.body.body);
+  this.inAsync = oldInAsync;
+  return this.finishNode(node, "FunctionExpression")
+};
+
+lp$2.parseArrowExpression = function(node, params, isAsync) {
+  var oldInAsync = this.inAsync;
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 8)
+    { node.async = !!isAsync; }
+  this.inAsync = node.async;
+  node.params = this.toAssignableList(params, true);
+  node.expression = this.tok.type !== __acorn.tokTypes.braceL;
+  if (node.expression) {
+    node.body = this.parseMaybeAssign();
+  } else {
+    node.body = this.parseBlock();
+    this.toks.adaptDirectivePrologue(node.body.body);
+  }
+  this.inAsync = oldInAsync;
+  return this.finishNode(node, "ArrowFunctionExpression")
+};
+
+lp$2.parseExprList = function(close, allowEmpty) {
+  var this$1 = this;
+
+  this.pushCx();
+  var indent = this.curIndent, line = this.curLineStart, elts = [];
+  this.next(); // Opening bracket
+  while (!this.closes(close, indent + 1, line)) {
+    if (this$1.eat(__acorn.tokTypes.comma)) {
+      elts.push(allowEmpty ? null : this$1.dummyIdent());
+      continue
+    }
+    var elt = this$1.parseMaybeAssign();
+    if (isDummy(elt)) {
+      if (this$1.closes(close, indent, line)) { break }
+      this$1.next();
+    } else {
+      elts.push(elt);
+    }
+    this$1.eat(__acorn.tokTypes.comma);
+  }
+  this.popCx();
+  if (!this.eat(close)) {
+    // If there is no closing brace, make the node span to the start
+    // of the next token (this is useful for Tern)
+    this.last.end = this.tok.start;
+    if (this.options.locations) { this.last.loc.end = this.tok.loc.start; }
+  }
+  return elts
+};
+
+lp$2.parseAwait = function() {
+  var node = this.startNode();
+  this.next();
+  node.argument = this.parseMaybeUnary();
+  return this.finishNode(node, "AwaitExpression")
+};
+
+// Acorn: Loose parser
+//
+// This module provides an alternative parser (`parse_dammit`) that
+// exposes that same interface as `parse`, but will try to parse
+// anything as JavaScript, repairing syntax error the best it can.
+// There are circumstances in which it will raise an error and give
+// up, but they are very rare. The resulting AST will be a mostly
+// valid JavaScript AST (as per the [Mozilla parser API][api], except
+// that:
+//
+// - Return outside functions is allowed
+//
+// - Label consistency (no conflicts, break only to existing labels)
+//   is not enforced.
+//
+// - Bogus Identifier nodes with a name of `"✖"` are inserted whenever
+//   the parser got too confused to return anything meaningful.
+//
+// [api]: https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API
+//
+// The expected use for this is to *first* try `acorn.parse`, and only
+// if that fails switch to `parse_dammit`. The loose parser might
+// parse badly indented code incorrectly, so **don't** use it as
+// your default parser.
+//
+// Quite a lot of acorn.js is duplicated here. The alternative was to
+// add a *lot* of extra cruft to that file, making it less readable
+// and slower. Copying and editing the code allowed me to make
+// invasive changes and simplifications without creating a complicated
+// tangle.
+
+__acorn.defaultOptions.tabSize = 4;
+
+// eslint-disable-next-line camelcase
+function parse_dammit(input, options) {
+  return new LooseParser(input, options).parse()
+}
+
+__acorn.addLooseExports(parse_dammit, LooseParser, pluginsLoose);
+
+exports.parse_dammit = parse_dammit;
+exports.LooseParser = LooseParser;
+exports.pluginsLoose = pluginsLoose;
+
+Object.defineProperty(exports, '__esModule', { value: true });
+
+})));
diff --git a/deps/acorn/dist/walk.es.js b/deps/acorn/dist/walk.es.js
new file mode 100644
index 0000000000..40356507d9
--- /dev/null
+++ b/deps/acorn/dist/walk.es.js
@@ -0,0 +1,407 @@
+// AST walker module for Mozilla Parser API compatible trees
+
+// A simple walk is one where you simply specify callbacks to be
+// called on specific nodes. The last two arguments are optional. A
+// simple use would be
+//
+//     walk.simple(myTree, {
+//         Expression: function(node) { ... }
+//     });
+//
+// to do something with all expressions. All Parser API node types
+// can be used to identify node types, as well as Expression,
+// Statement, and ScopeBody, which denote categories of nodes.
+//
+// The base argument can be used to pass a custom (recursive)
+// walker, and state can be used to give this walked an initial
+// state.
+
+function simple(node, visitors, base, state, override) {
+  if (!base) { base = exports.base
+  ; }(function c(node, st, override) {
+    var type = override || node.type, found = visitors[type];
+    base[type](node, st, c);
+    if (found) { found(node, st); }
+  })(node, state, override);
+}
+
+// An ancestor walk keeps an array of ancestor nodes (including the
+// current node) and passes them to the callback as third parameter
+// (and also as state parameter when no other state is present).
+function ancestor(node, visitors, base, state) {
+  if (!base) { base = exports.base; }
+  var ancestors = [];(function c(node, st, override) {
+    var type = override || node.type, found = visitors[type];
+    var isNew = node != ancestors[ancestors.length - 1];
+    if (isNew) { ancestors.push(node); }
+    base[type](node, st, c);
+    if (found) { found(node, st || ancestors, ancestors); }
+    if (isNew) { ancestors.pop(); }
+  })(node, state);
+}
+
+// A recursive walk is one where your functions override the default
+// walkers. They can modify and replace the state parameter that's
+// threaded through the walk, and can opt how and whether to walk
+// their child nodes (by calling their third argument on these
+// nodes).
+function recursive(node, state, funcs, base, override) {
+  var visitor = funcs ? exports.make(funcs, base) : base;(function c(node, st, override) {
+    visitor[override || node.type](node, st, c);
+  })(node, state, override);
+}
+
+function makeTest(test) {
+  if (typeof test == "string")
+    { return function (type) { return type == test; } }
+  else if (!test)
+    { return function () { return true; } }
+  else
+    { return test }
+}
+
+var Found = function Found(node, state) { this.node = node; this.state = state; };
+
+// A full walk triggers the callback on each node
+function full(node, callback, base, state, override) {
+  if (!base) { base = exports.base
+  ; }(function c(node, st, override) {
+    var type = override || node.type;
+    base[type](node, st, c);
+    if (!override) { callback(node, st, type); }
+  })(node, state, override);
+}
+
+// An fullAncestor walk is like an ancestor walk, but triggers
+// the callback on each node
+function fullAncestor(node, callback, base, state) {
+  if (!base) { base = exports.base; }
+  var ancestors = [];(function c(node, st, override) {
+    var type = override || node.type;
+    var isNew = node != ancestors[ancestors.length - 1];
+    if (isNew) { ancestors.push(node); }
+    base[type](node, st, c);
+    if (!override) { callback(node, st || ancestors, ancestors, type); }
+    if (isNew) { ancestors.pop(); }
+  })(node, state);
+}
+
+// Find a node with a given start, end, and type (all are optional,
+// null can be used as wildcard). Returns a {node, state} object, or
+// undefined when it doesn't find a matching node.
+function findNodeAt(node, start, end, test, base, state) {
+  test = makeTest(test);
+  if (!base) { base = exports.base; }
+  try {
+    (function c(node, st, override) {
+      var type = override || node.type;
+      if ((start == null || node.start <= start) &&
+          (end == null || node.end >= end))
+        { base[type](node, st, c); }
+      if ((start == null || node.start == start) &&
+          (end == null || node.end == end) &&
+          test(type, node))
+        { throw new Found(node, st) }
+    })(node, state);
+  } catch (e) {
+    if (e instanceof Found) { return e }
+    throw e
+  }
+}
+
+// Find the innermost node of a given type that contains the given
+// position. Interface similar to findNodeAt.
+function findNodeAround(node, pos, test, base, state) {
+  test = makeTest(test);
+  if (!base) { base = exports.base; }
+  try {
+    (function c(node, st, override) {
+      var type = override || node.type;
+      if (node.start > pos || node.end < pos) { return }
+      base[type](node, st, c);
+      if (test(type, node)) { throw new Found(node, st) }
+    })(node, state);
+  } catch (e) {
+    if (e instanceof Found) { return e }
+    throw e
+  }
+}
+
+// Find the outermost matching node after a given position.
+function findNodeAfter(node, pos, test, base, state) {
+  test = makeTest(test);
+  if (!base) { base = exports.base; }
+  try {
+    (function c(node, st, override) {
+      if (node.end < pos) { return }
+      var type = override || node.type;
+      if (node.start >= pos && test(type, node)) { throw new Found(node, st) }
+      base[type](node, st, c);
+    })(node, state);
+  } catch (e) {
+    if (e instanceof Found) { return e }
+    throw e
+  }
+}
+
+// Find the outermost matching node before a given position.
+function findNodeBefore(node, pos, test, base, state) {
+  test = makeTest(test);
+  if (!base) { base = exports.base; }
+  var max;(function c(node, st, override) {
+    if (node.start > pos) { return }
+    var type = override || node.type;
+    if (node.end <= pos && (!max || max.node.end < node.end) && test(type, node))
+      { max = new Found(node, st); }
+    base[type](node, st, c);
+  })(node, state);
+  return max
+}
+
+// Fallback to an Object.create polyfill for older environments.
+var create = Object.create || function(proto) {
+  function Ctor() {}
+  Ctor.prototype = proto;
+  return new Ctor
+};
+
+// Used to create a custom walker. Will fill in all missing node
+// type properties with the defaults.
+function make(funcs, base) {
+  if (!base) { base = exports.base; }
+  var visitor = create(base);
+  for (var type in funcs) { visitor[type] = funcs[type]; }
+  return visitor
+}
+
+function skipThrough(node, st, c) { c(node, st); }
+function ignore(_node, _st, _c) {}
+
+// Node walkers.
+
+var base = {};
+
+base.Program = base.BlockStatement = function (node, st, c) {
+  for (var i = 0, list = node.body; i < list.length; i += 1)
+    {
+    var stmt = list[i];
+
+    c(stmt, st, "Statement");
+  }
+};
+base.Statement = skipThrough;
+base.EmptyStatement = ignore;
+base.ExpressionStatement = base.ParenthesizedExpression =
+  function (node, st, c) { return c(node.expression, st, "Expression"); };
+base.IfStatement = function (node, st, c) {
+  c(node.test, st, "Expression");
+  c(node.consequent, st, "Statement");
+  if (node.alternate) { c(node.alternate, st, "Statement"); }
+};
+base.LabeledStatement = function (node, st, c) { return c(node.body, st, "Statement"); };
+base.BreakStatement = base.ContinueStatement = ignore;
+base.WithStatement = function (node, st, c) {
+  c(node.object, st, "Expression");
+  c(node.body, st, "Statement");
+};
+base.SwitchStatement = function (node, st, c) {
+  c(node.discriminant, st, "Expression");
+  for (var i = 0, list = node.cases; i < list.length; i += 1) {
+    var cs = list[i];
+
+    if (cs.test) { c(cs.test, st, "Expression"); }
+    for (var i$1 = 0, list$1 = cs.consequent; i$1 < list$1.length; i$1 += 1)
+      {
+      var cons = list$1[i$1];
+
+      c(cons, st, "Statement");
+    }
+  }
+};
+base.ReturnStatement = base.YieldExpression = base.AwaitExpression = function (node, st, c) {
+  if (node.argument) { c(node.argument, st, "Expression"); }
+};
+base.ThrowStatement = base.SpreadElement =
+  function (node, st, c) { return c(node.argument, st, "Expression"); };
+base.TryStatement = function (node, st, c) {
+  c(node.block, st, "Statement");
+  if (node.handler) { c(node.handler, st); }
+  if (node.finalizer) { c(node.finalizer, st, "Statement"); }
+};
+base.CatchClause = function (node, st, c) {
+  c(node.param, st, "Pattern");
+  c(node.body, st, "ScopeBody");
+};
+base.WhileStatement = base.DoWhileStatement = function (node, st, c) {
+  c(node.test, st, "Expression");
+  c(node.body, st, "Statement");
+};
+base.ForStatement = function (node, st, c) {
+  if (node.init) { c(node.init, st, "ForInit"); }
+  if (node.test) { c(node.test, st, "Expression"); }
+  if (node.update) { c(node.update, st, "Expression"); }
+  c(node.body, st, "Statement");
+};
+base.ForInStatement = base.ForOfStatement = function (node, st, c) {
+  c(node.left, st, "ForInit");
+  c(node.right, st, "Expression");
+  c(node.body, st, "Statement");
+};
+base.ForInit = function (node, st, c) {
+  if (node.type == "VariableDeclaration") { c(node, st); }
+  else { c(node, st, "Expression"); }
+};
+base.DebuggerStatement = ignore;
+
+base.FunctionDeclaration = function (node, st, c) { return c(node, st, "Function"); };
+base.VariableDeclaration = function (node, st, c) {
+  for (var i = 0, list = node.declarations; i < list.length; i += 1)
+    {
+    var decl = list[i];
+
+    c(decl, st);
+  }
+};
+base.VariableDeclarator = function (node, st, c) {
+  c(node.id, st, "Pattern");
+  if (node.init) { c(node.init, st, "Expression"); }
+};
+
+base.Function = function (node, st, c) {
+  if (node.id) { c(node.id, st, "Pattern"); }
+  for (var i = 0, list = node.params; i < list.length; i += 1)
+    {
+    var param = list[i];
+
+    c(param, st, "Pattern");
+  }
+  c(node.body, st, node.expression ? "ScopeExpression" : "ScopeBody");
+};
+// FIXME drop these node types in next major version
+// (They are awkward, and in ES6 every block can be a scope.)
+base.ScopeBody = function (node, st, c) { return c(node, st, "Statement"); };
+base.ScopeExpression = function (node, st, c) { return c(node, st, "Expression"); };
+
+base.Pattern = function (node, st, c) {
+  if (node.type == "Identifier")
+    { c(node, st, "VariablePattern"); }
+  else if (node.type == "MemberExpression")
+    { c(node, st, "MemberPattern"); }
+  else
+    { c(node, st); }
+};
+base.VariablePattern = ignore;
+base.MemberPattern = skipThrough;
+base.RestElement = function (node, st, c) { return c(node.argument, st, "Pattern"); };
+base.ArrayPattern = function (node, st, c) {
+  for (var i = 0, list = node.elements; i < list.length; i += 1) {
+    var elt = list[i];
+
+    if (elt) { c(elt, st, "Pattern"); }
+  }
+};
+base.ObjectPattern = function (node, st, c) {
+  for (var i = 0, list = node.properties; i < list.length; i += 1)
+    {
+    var prop = list[i];
+
+    c(prop.value, st, "Pattern");
+  }
+};
+
+base.Expression = skipThrough;
+base.ThisExpression = base.Super = base.MetaProperty = ignore;
+base.ArrayExpression = function (node, st, c) {
+  for (var i = 0, list = node.elements; i < list.length; i += 1) {
+    var elt = list[i];
+
+    if (elt) { c(elt, st, "Expression"); }
+  }
+};
+base.ObjectExpression = function (node, st, c) {
+  for (var i = 0, list = node.properties; i < list.length; i += 1)
+    {
+    var prop = list[i];
+
+    c(prop, st);
+  }
+};
+base.FunctionExpression = base.ArrowFunctionExpression = base.FunctionDeclaration;
+base.SequenceExpression = base.TemplateLiteral = function (node, st, c) {
+  for (var i = 0, list = node.expressions; i < list.length; i += 1)
+    {
+    var expr = list[i];
+
+    c(expr, st, "Expression");
+  }
+};
+base.UnaryExpression = base.UpdateExpression = function (node, st, c) {
+  c(node.argument, st, "Expression");
+};
+base.BinaryExpression = base.LogicalExpression = function (node, st, c) {
+  c(node.left, st, "Expression");
+  c(node.right, st, "Expression");
+};
+base.AssignmentExpression = base.AssignmentPattern = function (node, st, c) {
+  c(node.left, st, "Pattern");
+  c(node.right, st, "Expression");
+};
+base.ConditionalExpression = function (node, st, c) {
+  c(node.test, st, "Expression");
+  c(node.consequent, st, "Expression");
+  c(node.alternate, st, "Expression");
+};
+base.NewExpression = base.CallExpression = function (node, st, c) {
+  c(node.callee, st, "Expression");
+  if (node.arguments)
+    { for (var i = 0, list = node.arguments; i < list.length; i += 1)
+      {
+        var arg = list[i];
+
+        c(arg, st, "Expression");
+      } }
+};
+base.MemberExpression = function (node, st, c) {
+  c(node.object, st, "Expression");
+  if (node.computed) { c(node.property, st, "Expression"); }
+};
+base.ExportNamedDeclaration = base.ExportDefaultDeclaration = function (node, st, c) {
+  if (node.declaration)
+    { c(node.declaration, st, node.type == "ExportNamedDeclaration" || node.declaration.id ? "Statement" : "Expression"); }
+  if (node.source) { c(node.source, st, "Expression"); }
+};
+base.ExportAllDeclaration = function (node, st, c) {
+  c(node.source, st, "Expression");
+};
+base.ImportDeclaration = function (node, st, c) {
+  for (var i = 0, list = node.specifiers; i < list.length; i += 1)
+    {
+    var spec = list[i];
+
+    c(spec, st);
+  }
+  c(node.source, st, "Expression");
+};
+base.ImportSpecifier = base.ImportDefaultSpecifier = base.ImportNamespaceSpecifier = base.Identifier = base.Literal = ignore;
+
+base.TaggedTemplateExpression = function (node, st, c) {
+  c(node.tag, st, "Expression");
+  c(node.quasi, st);
+};
+base.ClassDeclaration = base.ClassExpression = function (node, st, c) { return c(node, st, "Class"); };
+base.Class = function (node, st, c) {
+  if (node.id) { c(node.id, st, "Pattern"); }
+  if (node.superClass) { c(node.superClass, st, "Expression"); }
+  for (var i = 0, list = node.body.body; i < list.length; i += 1)
+    {
+    var item = list[i];
+
+    c(item, st);
+  }
+};
+base.MethodDefinition = base.Property = function (node, st, c) {
+  if (node.computed) { c(node.key, st, "Expression"); }
+  c(node.value, st, "Expression");
+};
+
+export { simple, ancestor, recursive, full, fullAncestor, findNodeAt, findNodeAround, findNodeAfter, findNodeBefore, make, base };
diff --git a/deps/acorn/dist/walk.js b/deps/acorn/dist/walk.js
new file mode 100644
index 0000000000..b4fb694053
--- /dev/null
+++ b/deps/acorn/dist/walk.js
@@ -0,0 +1,427 @@
+(function (global, factory) {
+	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
+	typeof define === 'function' && define.amd ? define(['exports'], factory) :
+	(factory((global.acorn = global.acorn || {}, global.acorn.walk = global.acorn.walk || {})));
+}(this, (function (exports) { 'use strict';
+
+// AST walker module for Mozilla Parser API compatible trees
+
+// A simple walk is one where you simply specify callbacks to be
+// called on specific nodes. The last two arguments are optional. A
+// simple use would be
+//
+//     walk.simple(myTree, {
+//         Expression: function(node) { ... }
+//     });
+//
+// to do something with all expressions. All Parser API node types
+// can be used to identify node types, as well as Expression,
+// Statement, and ScopeBody, which denote categories of nodes.
+//
+// The base argument can be used to pass a custom (recursive)
+// walker, and state can be used to give this walked an initial
+// state.
+
+function simple(node, visitors, base, state, override) {
+  if (!base) { base = exports.base
+  ; }(function c(node, st, override) {
+    var type = override || node.type, found = visitors[type];
+    base[type](node, st, c);
+    if (found) { found(node, st); }
+  })(node, state, override);
+}
+
+// An ancestor walk keeps an array of ancestor nodes (including the
+// current node) and passes them to the callback as third parameter
+// (and also as state parameter when no other state is present).
+function ancestor(node, visitors, base, state) {
+  if (!base) { base = exports.base; }
+  var ancestors = [];(function c(node, st, override) {
+    var type = override || node.type, found = visitors[type];
+    var isNew = node != ancestors[ancestors.length - 1];
+    if (isNew) { ancestors.push(node); }
+    base[type](node, st, c);
+    if (found) { found(node, st || ancestors, ancestors); }
+    if (isNew) { ancestors.pop(); }
+  })(node, state);
+}
+
+// A recursive walk is one where your functions override the default
+// walkers. They can modify and replace the state parameter that's
+// threaded through the walk, and can opt how and whether to walk
+// their child nodes (by calling their third argument on these
+// nodes).
+function recursive(node, state, funcs, base, override) {
+  var visitor = funcs ? exports.make(funcs, base) : base;(function c(node, st, override) {
+    visitor[override || node.type](node, st, c);
+  })(node, state, override);
+}
+
+function makeTest(test) {
+  if (typeof test == "string")
+    { return function (type) { return type == test; } }
+  else if (!test)
+    { return function () { return true; } }
+  else
+    { return test }
+}
+
+var Found = function Found(node, state) { this.node = node; this.state = state; };
+
+// A full walk triggers the callback on each node
+function full(node, callback, base, state, override) {
+  if (!base) { base = exports.base
+  ; }(function c(node, st, override) {
+    var type = override || node.type;
+    base[type](node, st, c);
+    if (!override) { callback(node, st, type); }
+  })(node, state, override);
+}
+
+// An fullAncestor walk is like an ancestor walk, but triggers
+// the callback on each node
+function fullAncestor(node, callback, base, state) {
+  if (!base) { base = exports.base; }
+  var ancestors = [];(function c(node, st, override) {
+    var type = override || node.type;
+    var isNew = node != ancestors[ancestors.length - 1];
+    if (isNew) { ancestors.push(node); }
+    base[type](node, st, c);
+    if (!override) { callback(node, st || ancestors, ancestors, type); }
+    if (isNew) { ancestors.pop(); }
+  })(node, state);
+}
+
+// Find a node with a given start, end, and type (all are optional,
+// null can be used as wildcard). Returns a {node, state} object, or
+// undefined when it doesn't find a matching node.
+function findNodeAt(node, start, end, test, base, state) {
+  test = makeTest(test);
+  if (!base) { base = exports.base; }
+  try {
+    (function c(node, st, override) {
+      var type = override || node.type;
+      if ((start == null || node.start <= start) &&
+          (end == null || node.end >= end))
+        { base[type](node, st, c); }
+      if ((start == null || node.start == start) &&
+          (end == null || node.end == end) &&
+          test(type, node))
+        { throw new Found(node, st) }
+    })(node, state);
+  } catch (e) {
+    if (e instanceof Found) { return e }
+    throw e
+  }
+}
+
+// Find the innermost node of a given type that contains the given
+// position. Interface similar to findNodeAt.
+function findNodeAround(node, pos, test, base, state) {
+  test = makeTest(test);
+  if (!base) { base = exports.base; }
+  try {
+    (function c(node, st, override) {
+      var type = override || node.type;
+      if (node.start > pos || node.end < pos) { return }
+      base[type](node, st, c);
+      if (test(type, node)) { throw new Found(node, st) }
+    })(node, state);
+  } catch (e) {
+    if (e instanceof Found) { return e }
+    throw e
+  }
+}
+
+// Find the outermost matching node after a given position.
+function findNodeAfter(node, pos, test, base, state) {
+  test = makeTest(test);
+  if (!base) { base = exports.base; }
+  try {
+    (function c(node, st, override) {
+      if (node.end < pos) { return }
+      var type = override || node.type;
+      if (node.start >= pos && test(type, node)) { throw new Found(node, st) }
+      base[type](node, st, c);
+    })(node, state);
+  } catch (e) {
+    if (e instanceof Found) { return e }
+    throw e
+  }
+}
+
+// Find the outermost matching node before a given position.
+function findNodeBefore(node, pos, test, base, state) {
+  test = makeTest(test);
+  if (!base) { base = exports.base; }
+  var max;(function c(node, st, override) {
+    if (node.start > pos) { return }
+    var type = override || node.type;
+    if (node.end <= pos && (!max || max.node.end < node.end) && test(type, node))
+      { max = new Found(node, st); }
+    base[type](node, st, c);
+  })(node, state);
+  return max
+}
+
+// Fallback to an Object.create polyfill for older environments.
+var create = Object.create || function(proto) {
+  function Ctor() {}
+  Ctor.prototype = proto;
+  return new Ctor
+};
+
+// Used to create a custom walker. Will fill in all missing node
+// type properties with the defaults.
+function make(funcs, base) {
+  if (!base) { base = exports.base; }
+  var visitor = create(base);
+  for (var type in funcs) { visitor[type] = funcs[type]; }
+  return visitor
+}
+
+function skipThrough(node, st, c) { c(node, st); }
+function ignore(_node, _st, _c) {}
+
+// Node walkers.
+
+var base = {};
+
+base.Program = base.BlockStatement = function (node, st, c) {
+  for (var i = 0, list = node.body; i < list.length; i += 1)
+    {
+    var stmt = list[i];
+
+    c(stmt, st, "Statement");
+  }
+};
+base.Statement = skipThrough;
+base.EmptyStatement = ignore;
+base.ExpressionStatement = base.ParenthesizedExpression =
+  function (node, st, c) { return c(node.expression, st, "Expression"); };
+base.IfStatement = function (node, st, c) {
+  c(node.test, st, "Expression");
+  c(node.consequent, st, "Statement");
+  if (node.alternate) { c(node.alternate, st, "Statement"); }
+};
+base.LabeledStatement = function (node, st, c) { return c(node.body, st, "Statement"); };
+base.BreakStatement = base.ContinueStatement = ignore;
+base.WithStatement = function (node, st, c) {
+  c(node.object, st, "Expression");
+  c(node.body, st, "Statement");
+};
+base.SwitchStatement = function (node, st, c) {
+  c(node.discriminant, st, "Expression");
+  for (var i = 0, list = node.cases; i < list.length; i += 1) {
+    var cs = list[i];
+
+    if (cs.test) { c(cs.test, st, "Expression"); }
+    for (var i$1 = 0, list$1 = cs.consequent; i$1 < list$1.length; i$1 += 1)
+      {
+      var cons = list$1[i$1];
+
+      c(cons, st, "Statement");
+    }
+  }
+};
+base.ReturnStatement = base.YieldExpression = base.AwaitExpression = function (node, st, c) {
+  if (node.argument) { c(node.argument, st, "Expression"); }
+};
+base.ThrowStatement = base.SpreadElement =
+  function (node, st, c) { return c(node.argument, st, "Expression"); };
+base.TryStatement = function (node, st, c) {
+  c(node.block, st, "Statement");
+  if (node.handler) { c(node.handler, st); }
+  if (node.finalizer) { c(node.finalizer, st, "Statement"); }
+};
+base.CatchClause = function (node, st, c) {
+  c(node.param, st, "Pattern");
+  c(node.body, st, "ScopeBody");
+};
+base.WhileStatement = base.DoWhileStatement = function (node, st, c) {
+  c(node.test, st, "Expression");
+  c(node.body, st, "Statement");
+};
+base.ForStatement = function (node, st, c) {
+  if (node.init) { c(node.init, st, "ForInit"); }
+  if (node.test) { c(node.test, st, "Expression"); }
+  if (node.update) { c(node.update, st, "Expression"); }
+  c(node.body, st, "Statement");
+};
+base.ForInStatement = base.ForOfStatement = function (node, st, c) {
+  c(node.left, st, "ForInit");
+  c(node.right, st, "Expression");
+  c(node.body, st, "Statement");
+};
+base.ForInit = function (node, st, c) {
+  if (node.type == "VariableDeclaration") { c(node, st); }
+  else { c(node, st, "Expression"); }
+};
+base.DebuggerStatement = ignore;
+
+base.FunctionDeclaration = function (node, st, c) { return c(node, st, "Function"); };
+base.VariableDeclaration = function (node, st, c) {
+  for (var i = 0, list = node.declarations; i < list.length; i += 1)
+    {
+    var decl = list[i];
+
+    c(decl, st);
+  }
+};
+base.VariableDeclarator = function (node, st, c) {
+  c(node.id, st, "Pattern");
+  if (node.init) { c(node.init, st, "Expression"); }
+};
+
+base.Function = function (node, st, c) {
+  if (node.id) { c(node.id, st, "Pattern"); }
+  for (var i = 0, list = node.params; i < list.length; i += 1)
+    {
+    var param = list[i];
+
+    c(param, st, "Pattern");
+  }
+  c(node.body, st, node.expression ? "ScopeExpression" : "ScopeBody");
+};
+// FIXME drop these node types in next major version
+// (They are awkward, and in ES6 every block can be a scope.)
+base.ScopeBody = function (node, st, c) { return c(node, st, "Statement"); };
+base.ScopeExpression = function (node, st, c) { return c(node, st, "Expression"); };
+
+base.Pattern = function (node, st, c) {
+  if (node.type == "Identifier")
+    { c(node, st, "VariablePattern"); }
+  else if (node.type == "MemberExpression")
+    { c(node, st, "MemberPattern"); }
+  else
+    { c(node, st); }
+};
+base.VariablePattern = ignore;
+base.MemberPattern = skipThrough;
+base.RestElement = function (node, st, c) { return c(node.argument, st, "Pattern"); };
+base.ArrayPattern = function (node, st, c) {
+  for (var i = 0, list = node.elements; i < list.length; i += 1) {
+    var elt = list[i];
+
+    if (elt) { c(elt, st, "Pattern"); }
+  }
+};
+base.ObjectPattern = function (node, st, c) {
+  for (var i = 0, list = node.properties; i < list.length; i += 1)
+    {
+    var prop = list[i];
+
+    c(prop.value, st, "Pattern");
+  }
+};
+
+base.Expression = skipThrough;
+base.ThisExpression = base.Super = base.MetaProperty = ignore;
+base.ArrayExpression = function (node, st, c) {
+  for (var i = 0, list = node.elements; i < list.length; i += 1) {
+    var elt = list[i];
+
+    if (elt) { c(elt, st, "Expression"); }
+  }
+};
+base.ObjectExpression = function (node, st, c) {
+  for (var i = 0, list = node.properties; i < list.length; i += 1)
+    {
+    var prop = list[i];
+
+    c(prop, st);
+  }
+};
+base.FunctionExpression = base.ArrowFunctionExpression = base.FunctionDeclaration;
+base.SequenceExpression = base.TemplateLiteral = function (node, st, c) {
+  for (var i = 0, list = node.expressions; i < list.length; i += 1)
+    {
+    var expr = list[i];
+
+    c(expr, st, "Expression");
+  }
+};
+base.UnaryExpression = base.UpdateExpression = function (node, st, c) {
+  c(node.argument, st, "Expression");
+};
+base.BinaryExpression = base.LogicalExpression = function (node, st, c) {
+  c(node.left, st, "Expression");
+  c(node.right, st, "Expression");
+};
+base.AssignmentExpression = base.AssignmentPattern = function (node, st, c) {
+  c(node.left, st, "Pattern");
+  c(node.right, st, "Expression");
+};
+base.ConditionalExpression = function (node, st, c) {
+  c(node.test, st, "Expression");
+  c(node.consequent, st, "Expression");
+  c(node.alternate, st, "Expression");
+};
+base.NewExpression = base.CallExpression = function (node, st, c) {
+  c(node.callee, st, "Expression");
+  if (node.arguments)
+    { for (var i = 0, list = node.arguments; i < list.length; i += 1)
+      {
+        var arg = list[i];
+
+        c(arg, st, "Expression");
+      } }
+};
+base.MemberExpression = function (node, st, c) {
+  c(node.object, st, "Expression");
+  if (node.computed) { c(node.property, st, "Expression"); }
+};
+base.ExportNamedDeclaration = base.ExportDefaultDeclaration = function (node, st, c) {
+  if (node.declaration)
+    { c(node.declaration, st, node.type == "ExportNamedDeclaration" || node.declaration.id ? "Statement" : "Expression"); }
+  if (node.source) { c(node.source, st, "Expression"); }
+};
+base.ExportAllDeclaration = function (node, st, c) {
+  c(node.source, st, "Expression");
+};
+base.ImportDeclaration = function (node, st, c) {
+  for (var i = 0, list = node.specifiers; i < list.length; i += 1)
+    {
+    var spec = list[i];
+
+    c(spec, st);
+  }
+  c(node.source, st, "Expression");
+};
+base.ImportSpecifier = base.ImportDefaultSpecifier = base.ImportNamespaceSpecifier = base.Identifier = base.Literal = ignore;
+
+base.TaggedTemplateExpression = function (node, st, c) {
+  c(node.tag, st, "Expression");
+  c(node.quasi, st);
+};
+base.ClassDeclaration = base.ClassExpression = function (node, st, c) { return c(node, st, "Class"); };
+base.Class = function (node, st, c) {
+  if (node.id) { c(node.id, st, "Pattern"); }
+  if (node.superClass) { c(node.superClass, st, "Expression"); }
+  for (var i = 0, list = node.body.body; i < list.length; i += 1)
+    {
+    var item = list[i];
+
+    c(item, st);
+  }
+};
+base.MethodDefinition = base.Property = function (node, st, c) {
+  if (node.computed) { c(node.key, st, "Expression"); }
+  c(node.value, st, "Expression");
+};
+
+exports.simple = simple;
+exports.ancestor = ancestor;
+exports.recursive = recursive;
+exports.full = full;
+exports.fullAncestor = fullAncestor;
+exports.findNodeAt = findNodeAt;
+exports.findNodeAround = findNodeAround;
+exports.findNodeAfter = findNodeAfter;
+exports.findNodeBefore = findNodeBefore;
+exports.make = make;
+exports.base = base;
+
+Object.defineProperty(exports, '__esModule', { value: true });
+
+})));
diff --git a/deps/acorn/package.json b/deps/acorn/package.json
new file mode 100644
index 0000000000..56c63a4a93
--- /dev/null
+++ b/deps/acorn/package.json
@@ -0,0 +1,52 @@
+{
+  "name": "acorn",
+  "description": "ECMAScript parser",
+  "homepage": "https://github.com/ternjs/acorn",
+  "main": "dist/acorn.js",
+  "module": "dist/acorn.es.js",
+  "version": "5.2.1",
+  "engines": {
+    "node": ">=0.4.0"
+  },
+  "maintainers": [
+    {
+      "name": "Marijn Haverbeke",
+      "email": "marijnh@gmail.com",
+      "web": "http://marijnhaverbeke.nl"
+    },
+    {
+      "name": "Ingvar Stepanyan",
+      "email": "me@rreverser.com",
+      "web": "http://rreverser.com/"
+    }
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/ternjs/acorn.git"
+  },
+  "license": "MIT",
+  "scripts": {
+    "prepare": "npm test",
+    "test": "node test/run.js && node test/lint.js",
+    "pretest": "npm run build:main && npm run build:loose",
+    "build": "npm run build:main && npm run build:walk && npm run build:loose && npm run build:bin",
+    "build:main": "rollup -c rollup/config.main.js",
+    "build:walk": "rollup -c rollup/config.walk.js",
+    "build:loose": "rollup -c rollup/config.loose.js && rollup -c rollup/config.loose_es.js",
+    "build:bin": "rollup -c rollup/config.bin.js",
+    "lint": "eslint src/"
+  },
+  "bin": {
+    "acorn": "./bin/acorn"
+  },
+  "devDependencies": {
+    "eslint": "^3.18.0",
+    "eslint-config-standard": "^7.1.0",
+    "eslint-plugin-import": "^2.2.0",
+    "eslint-plugin-promise": "^3.5.0",
+    "eslint-plugin-standard": "^2.1.1",
+    "rollup": "^0.43.0",
+    "rollup-plugin-buble": "^0.15.0",
+    "unicode-9.0.0": "^0.7.0"
+  }
+}