Move Extension type to ghc-boot-th

This creates a new package, `ghc-boot-th`, to contain the `Extension`
type, which now lives in `GHC.LanguageExtension.Type`. This ensures that
the transitive dependency set of the `template-haskell` package remains
minimal.

The `GHC.LanguageExtensions.Type` module is also re-exported by
`ghc-boot`, which provides an orphan `binary` instance as well.

Test Plan: Validate

Reviewers: goldfire, thomie, hvr, austin

Reviewed By: thomie

Subscribers: RyanGlScott, thomie, erikd, ezyang

Differential Revision: https://phabricator.haskell.org/D2224

5 files changed, 237 insertions, 0 deletions

diff --git a/libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs b/libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs
new file mode 100644
index 0000000000..39613b0c4b
--- /dev/null
+++ b/libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs
@@ -0,0 +1,132 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  GHC.LanguageExtensions.Type
+-- Copyright   :  (c) The GHC Team
+--
+-- Maintainer  :  ghc-devs@haskell.org
+-- Portability :  portable
+--
+-- A data type defining the language extensions supported by GHC.
+--
+{-# LANGUAGE DeriveGeneric #-}
+module GHC.LanguageExtensions.Type ( Extension(..) ) where
+
+import GHC.Generics
+
+-- | The language extensions known to GHC.
+--
+-- Note that there is an orphan 'Binary' instance for this type supplied by
+-- the "GHC.LanguageExtensions" module provided by @ghc-boot@. We can't provide
+-- here as this would require adding transitive dependencies to the
+-- @template-haskell@ package, which must have a minimal dependency set.
+data Extension
+-- See Note [Updating flag description in the User's Guide] in DynFlags
+   = Cpp
+   | OverlappingInstances
+   | UndecidableInstances
+   | IncoherentInstances
+   | UndecidableSuperClasses
+   | MonomorphismRestriction
+   | MonoPatBinds
+   | MonoLocalBinds
+   | RelaxedPolyRec           -- Deprecated
+   | ExtendedDefaultRules     -- Use GHC's extended rules for defaulting
+   | ForeignFunctionInterface
+   | UnliftedFFITypes
+   | InterruptibleFFI
+   | CApiFFI
+   | GHCForeignImportPrim
+   | JavaScriptFFI
+   | ParallelArrays           -- Syntactic support for parallel arrays
+   | Arrows                   -- Arrow-notation syntax
+   | TemplateHaskell
+   | TemplateHaskellQuotes    -- subset of TH supported by stage1, no splice
+   | QuasiQuotes
+   | ImplicitParams
+   | ImplicitPrelude
+   | ScopedTypeVariables
+   | AllowAmbiguousTypes
+   | UnboxedTuples
+   | BangPatterns
+   | TypeFamilies
+   | TypeFamilyDependencies
+   | TypeInType
+   | OverloadedStrings
+   | OverloadedLists
+   | NumDecimals
+   | DisambiguateRecordFields
+   | RecordWildCards
+   | RecordPuns
+   | ViewPatterns
+   | GADTs
+   | GADTSyntax
+   | NPlusKPatterns
+   | DoAndIfThenElse
+   | RebindableSyntax
+   | ConstraintKinds
+   | PolyKinds                -- Kind polymorphism
+   | DataKinds                -- Datatype promotion
+   | InstanceSigs
+   | ApplicativeDo
+
+   | StandaloneDeriving
+   | DeriveDataTypeable
+   | AutoDeriveTypeable       -- Automatic derivation of Typeable
+   | DeriveFunctor
+   | DeriveTraversable
+   | DeriveFoldable
+   | DeriveGeneric            -- Allow deriving Generic/1
+   | DefaultSignatures        -- Allow extra signatures for defmeths
+   | DeriveAnyClass           -- Allow deriving any class
+   | DeriveLift               -- Allow deriving Lift
+
+   | TypeSynonymInstances
+   | FlexibleContexts
+   | FlexibleInstances
+   | ConstrainedClassMethods
+   | MultiParamTypeClasses
+   | NullaryTypeClasses
+   | FunctionalDependencies
+   | UnicodeSyntax
+   | ExistentialQuantification
+   | MagicHash
+   | EmptyDataDecls
+   | KindSignatures
+   | RoleAnnotations
+   | ParallelListComp
+   | TransformListComp
+   | MonadComprehensions
+   | GeneralizedNewtypeDeriving
+   | RecursiveDo
+   | PostfixOperators
+   | TupleSections
+   | PatternGuards
+   | LiberalTypeSynonyms
+   | RankNTypes
+   | ImpredicativeTypes
+   | TypeOperators
+   | ExplicitNamespaces
+   | PackageImports
+   | ExplicitForAll
+   | AlternativeLayoutRule
+   | AlternativeLayoutRuleTransitional
+   | DatatypeContexts
+   | NondecreasingIndentation
+   | RelaxedLayout
+   | TraditionalRecordSyntax
+   | LambdaCase
+   | MultiWayIf
+   | BinaryLiterals
+   | NegativeLiterals
+   | DuplicateRecordFields
+   | OverloadedLabels
+   | EmptyCase
+   | PatternSynonyms
+   | PartialTypeSignatures
+   | NamedWildCards
+   | StaticPointers
+   | TypeApplications
+   | Strict
+   | StrictData
+   | MonadFailDesugaring
+   deriving (Eq, Enum, Show, Generic)
diff --git a/libraries/ghc-boot-th/GHC/Lexeme.hs b/libraries/ghc-boot-th/GHC/Lexeme.hs
new file mode 100644
index 0000000000..677c9a65e6
--- /dev/null
+++ b/libraries/ghc-boot-th/GHC/Lexeme.hs
@@ -0,0 +1,32 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  GHC.Lexeme
+-- Copyright   :  (c) The GHC Team
+--
+-- Maintainer  :  ghc-devs@haskell.org
+-- Portability :  portable
+--
+-- Functions to evaluate whether or not a string is a valid identifier.
+--
+module GHC.Lexeme (
+          -- * Lexical characteristics of Haskell names
+        startsVarSym, startsVarId, startsConSym, startsConId,
+        startsVarSymASCII, isVarSymChar
+  ) where
+
+import Data.Char
+
+startsVarSym, startsVarId, startsConSym, startsConId :: Char -> Bool
+startsVarSym c = startsVarSymASCII c || (ord c > 0x7f && isSymbol c)  -- Infix Ids
+startsConSym c = c == ':'               -- Infix data constructors
+startsVarId c  = c == '_' || case generalCategory c of  -- Ordinary Ids
+  LowercaseLetter -> True
+  OtherLetter     -> True   -- See #1103
+  _               -> False
+startsConId c  = isUpper c || c == '('  -- Ordinary type constructors and data constructors
+
+startsVarSymASCII :: Char -> Bool
+startsVarSymASCII c = c `elem` "!#$%&*+./<=>?@\\^|~-"
+
+isVarSymChar :: Char -> Bool
+isVarSymChar c = c == ':' || startsVarSym c
diff --git a/libraries/ghc-boot-th/LICENSE b/libraries/ghc-boot-th/LICENSE
new file mode 100644
index 0000000000..b5059b71f6
--- /dev/null
+++ b/libraries/ghc-boot-th/LICENSE
@@ -0,0 +1,31 @@
+The Glasgow Haskell Compiler License
+
+Copyright 2002, The University Court of the University of Glasgow. 
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+- Redistributions of source code must retain the above copyright notice,
+this list of conditions and the following disclaimer.
+ 
+- Redistributions in binary form must reproduce the above copyright notice,
+this list of conditions and the following disclaimer in the documentation
+and/or other materials provided with the distribution.
+ 
+- Neither name of the University nor the names of its contributors may be
+used to endorse or promote products derived from this software without
+specific prior written permission. 
+
+THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY COURT OF THE UNIVERSITY OF
+GLASGOW AND THE CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+UNIVERSITY COURT OF THE UNIVERSITY OF GLASGOW OR THE CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+DAMAGE.
diff --git a/libraries/ghc-boot-th/changelog.md b/libraries/ghc-boot-th/changelog.md
new file mode 100644
index 0000000000..3ed5bbbfd2
--- /dev/null
+++ b/libraries/ghc-boot-th/changelog.md
@@ -0,0 +1,5 @@
+## 8.0.1  *May 2016*
+
+  * Bundled with GHC 8.0.1
+
+  * Initial version
diff --git a/libraries/ghc-boot-th/ghc-boot-th.cabal.in b/libraries/ghc-boot-th/ghc-boot-th.cabal.in
new file mode 100644
index 0000000000..3aebfbfc89
--- /dev/null
+++ b/libraries/ghc-boot-th/ghc-boot-th.cabal.in
@@ -0,0 +1,37 @@
+-- WARNING: ghc-boot-th.cabal is automatically generated from
+-- ghc-boot-th.cabal.in by ../../configure.  Make sure you are editing
+-- ghc-boot-th.cabal.in, not ghc-boot-th.cabal.
+
+name:           ghc-boot-th
+version:        @ProjectVersionMunged@
+license:        BSD3
+license-file:   LICENSE
+category:       GHC
+maintainer:     ghc-devs@haskell.org
+bug-reports:    https://ghc.haskell.org/trac/ghc/newticket
+synopsis:       Shared functionality between GHC and the @template-haskell@
+                library
+description:    This library contains various bits shared between the @ghc@ and
+                @template-haskell@ libraries.
+                .
+                This package exists to ensure that @template-haskell@ has a
+                minimal set of transitive dependencies, since it is intended to
+                be depended upon by user code.
+cabal-version:  >=1.10
+build-type:     Simple
+extra-source-files: changelog.md
+
+source-repository head
+    type:     git
+    location: http://git.haskell.org/ghc.git
+    subdir:   libraries/ghc-boot-th
+
+Library
+    default-language: Haskell2010
+    other-extensions: DeriveGeneric
+
+    exposed-modules:
+            GHC.LanguageExtensions.Type
+            GHC.Lexeme
+
+    build-depends: base       >= 4.7 && < 4.10