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from __future__ import absolute_import
from __future__ import print_function
import logging
import six
from scss.types import Value, Undefined
log = logging.getLogger(__name__)
SORTED_SELECTORS = False
sort = sorted if SORTED_SELECTORS else lambda it: it
def normalize_var(name):
if isinstance(name, six.string_types):
return name.replace('_', '-')
else:
log.warn("Variable name doesn't look like a string: %r", name)
return name
def extend_unique(seq, more):
"""Return a new sequence containing the items in `seq` plus any items in
`more` that aren't already in `seq`, preserving the order of both.
"""
seen = set(seq)
new = []
for item in more:
if item not in seen:
seen.add(item)
new.append(item)
return seq + type(seq)(new)
class Scope(object):
"""Implements Sass variable scoping.
Similar to `ChainMap`, except that assigning a new value will replace an
existing value, not mask it.
"""
def __init__(self, maps=()):
maps = list(maps)
assert all(isinstance(m, dict) or isinstance(m, type(self)) for m in maps) # Check all passed maps are compatible with the current Scope
self.maps = [dict()] + maps
def __repr__(self):
return "<%s(%s) at 0x%x>" % (type(self).__name__, ', '.join(repr(map) for map in self.maps), id(self))
def __getitem__(self, key):
for map in self.maps:
if key in map:
return map[key]
raise KeyError(key)
def __setitem__(self, key, value):
self.set(key, value)
def __contains__(self, key):
try:
self[key]
except KeyError:
return False
else:
return True
def keys(self):
# For mapping interface
keys = set()
for map in self.maps:
keys.update(map.keys())
return list(keys)
def set(self, key, value, force_local=False):
if not force_local:
for map in self.maps:
if key in map:
if isinstance(map[key], Undefined):
break
map[key] = value
return
self.maps[0][key] = value
def new_child(self):
return type(self)(self.maps)
class VariableScope(Scope):
pass
class FunctionScope(Scope):
def __repr__(self):
return "<%s(%s) at 0x%x>" % (type(self).__name__, ', '.join('[%s]' % ', '.join('%s:%s' % (f, n) for f, n in sorted(map.keys())) for map in self.maps), id(self))
class MixinScope(Scope):
def __repr__(self):
return "<%s(%s) at 0x%x>" % (type(self).__name__, ', '.join('[%s]' % ', '.join('%s:%s' % (f, n) for f, n in sorted(map.keys())) for map in self.maps), id(self))
class ImportScope(Scope):
pass
class Namespace(object):
"""..."""
_mutable = True
def __init__(self, variables=None, functions=None, mixins=None, mutable=True):
self._mutable = mutable
if variables is None:
self._variables = VariableScope()
else:
# TODO parse into sass values once that's a thing, or require them
# all to be
self._variables = VariableScope([variables])
if functions is None:
self._functions = FunctionScope()
else:
self._functions = FunctionScope([functions._functions])
self._mixins = MixinScope()
self._imports = ImportScope()
def _assert_mutable(self):
if not self._mutable:
raise AttributeError("This Namespace instance is immutable")
@classmethod
def derive_from(cls, *others):
self = cls()
if len(others) == 1:
self._variables = others[0]._variables.new_child()
self._functions = others[0]._functions.new_child()
self._mixins = others[0]._mixins.new_child()
self._imports = others[0]._imports.new_child()
else:
# Note that this will create a 2-dimensional scope where each of
# these scopes is checked first in order. TODO is this right?
self._variables = VariableScope(other._variables for other in others)
self._functions = FunctionScope(other._functions for other in others)
self._mixins = MixinScope(other._mixins for other in others)
self._imports = ImportScope(other._imports for other in others)
return self
def derive(self):
"""Return a new child namespace. All existing variables are still
readable and writeable, but any new variables will only exist within a
new scope.
"""
return type(self).derive_from(self)
@property
def variables(self):
return dict((k, self._variables[k]) for k in self._variables.keys())
def variable(self, name, throw=False):
name = normalize_var(name)
return self._variables[name]
def set_variable(self, name, value, local_only=False):
self._assert_mutable()
name = normalize_var(name)
if not isinstance(value, Value):
raise TypeError("Expected a Sass type, while setting %s got %r" % (name, value,))
self._variables.set(name, value, force_local=local_only)
def has_import(self, import_key):
return import_key in self._imports
def add_import(self, import_key, parent_import_key, file_and_line):
self._assert_mutable()
if import_key:
imports = [0, parent_import_key, file_and_line]
self._imports[import_key] = imports
def use_import(self, import_key):
self._assert_mutable()
if import_key and import_key in self._imports:
imports = self._imports[import_key]
imports[0] += 1
self.use_import(imports[1])
def unused_imports(self):
unused = []
for import_key in self._imports.keys():
imports = self._imports[import_key]
if not imports[0]:
unused.append((import_key[0], imports[2]))
return unused
def _get_callable(self, chainmap, name, arity):
name = normalize_var(name)
if arity is not None:
# With explicit arity, try the particular arity before falling back
# to the general case (None)
try:
return chainmap[name, arity]
except KeyError:
pass
return chainmap[name, None]
def _set_callable(self, chainmap, name, arity, cb):
name = normalize_var(name)
chainmap[name, arity] = cb
def mixin(self, name, arity):
return self._get_callable(self._mixins, name, arity)
def set_mixin(self, name, arity, cb):
self._assert_mutable()
self._set_callable(self._mixins, name, arity, cb)
def function(self, name, arity):
return self._get_callable(self._functions, name, arity)
def set_function(self, name, arity, cb):
self._assert_mutable()
self._set_callable(self._functions, name, arity, cb)
class SassRule(object):
"""At its heart, a CSS rule: combination of a selector and zero or more
properties. But this is Sass, so it also tracks some Sass-flavored
metadata, like `@extend` rules and `@media` nesting.
"""
def __init__(self, source_file, import_key=None, unparsed_contents=None,
options=None, properties=None,
namespace=None,
lineno=0, extends_selectors=frozenset(),
ancestry=None,
nested=0):
self.source_file = source_file
self.import_key = import_key
self.lineno = lineno
self.unparsed_contents = unparsed_contents
self.options = options
self.extends_selectors = extends_selectors
if namespace is None:
assert False
self.namespace = Namespace()
else:
self.namespace = namespace
if properties is None:
self.properties = []
else:
self.properties = properties
self.retval = None
if ancestry is None:
self.ancestry = RuleAncestry()
else:
self.ancestry = ancestry
self.nested = nested
self.descendants = 0
def __repr__(self):
return "<SassRule %s, %d props>" % (
self.ancestry,
len(self.properties),
)
@property
def selectors(self):
# TEMPORARY
if self.ancestry.headers and self.ancestry.headers[-1].is_selector:
return self.ancestry.headers[-1].selectors
else:
return ()
@property
def file_and_line(self):
"""Return the filename and line number where this rule originally
appears, in the form "foo.scss:3". Used for error messages.
"""
return "%s:%d" % (self.source_file.filename, self.lineno)
@property
def is_empty(self):
"""Return whether this rule is considered "empty" -- i.e., has no
contents that should end up in the final CSS.
"""
if self.properties:
# Rules containing CSS properties are never empty
return False
if not self.descendants:
for header in self.ancestry.headers:
if header.is_atrule and header.directive != '@media':
# At-rules should always be preserved, UNLESS they are @media
# blocks, which are known to be noise if they don't have any
# contents of their own
return False
return True
def copy(self):
return type(self)(
source_file=self.source_file,
lineno=self.lineno,
unparsed_contents=self.unparsed_contents,
options=self.options,
#properties=list(self.properties),
properties=self.properties,
extends_selectors=self.extends_selectors,
#ancestry=list(self.ancestry),
ancestry=self.ancestry,
namespace=self.namespace.derive(),
nested=self.nested,
)
class RuleAncestry(object):
def __init__(self, headers=()):
self.headers = tuple(headers)
def __repr__(self):
return "<%s %r>" % (type(self).__name__, self.headers)
def __len__(self):
return len(self.headers)
def with_nested_selectors(self, c_selectors):
if self.headers and self.headers[-1].is_selector:
# Need to merge with parent selectors
p_selectors = self.headers[-1].selectors
new_selectors = []
for p_selector in p_selectors:
for c_selector in c_selectors:
new_selectors.append(c_selector.with_parent(p_selector))
# Replace the last header with the new merged selectors
new_headers = self.headers[:-1] + (BlockSelectorHeader(new_selectors),)
return RuleAncestry(new_headers)
else:
# Whoops, no parent selectors. Just need to double-check that
# there are no uses of `&`.
for c_selector in c_selectors:
if c_selector.has_parent_reference:
raise ValueError("Can't use parent selector '&' in top-level rules")
# Add the children as a new header
new_headers = self.headers + (BlockSelectorHeader(c_selectors),)
return RuleAncestry(new_headers)
def with_more_selectors(self, selectors):
"""Return a new ancestry that also matches the given selectors. No
nesting is done.
"""
if self.headers and self.headers[-1].is_selector:
new_selectors = extend_unique(
self.headers[-1].selectors,
selectors)
new_headers = self.headers[:-1] + (
BlockSelectorHeader(new_selectors),)
return RuleAncestry(new_headers)
else:
new_headers = self.headers + (BlockSelectorHeader(selectors),)
return RuleAncestry(new_headers)
class BlockHeader(object):
"""..."""
# TODO doc me depending on how UnparsedBlock is handled...
is_atrule = False
is_scope = False
is_selector = False
@classmethod
def parse(cls, prop, has_contents=False):
# Simple pre-processing
if prop.startswith('+') and not has_contents:
# Expand '+' at the beginning of a rule as @include. But not if
# there's a block, because that's probably a CSS selector.
# DEVIATION: this is some semi hybrid of Sass and xCSS syntax
prop = '@include ' + prop[1:]
try:
if '(' not in prop or prop.index(':') < prop.index('('):
prop = prop.replace(':', '(', 1)
if '(' in prop:
prop += ')'
except ValueError:
pass
elif prop.startswith('='):
# Expand '=' at the beginning of a rule as @mixin
prop = '@mixin ' + prop[1:]
elif prop.startswith('@prototype '):
# Remove '@prototype '
# TODO what is @prototype??
prop = prop[11:]
# Minor parsing
if prop.startswith('@'):
if prop.lower().startswith('@else if '):
directive = '@else if'
argument = prop[9:]
else:
directive, _, argument = prop.partition(' ')
directive = directive.lower()
return BlockAtRuleHeader(directive, argument)
else:
if prop.endswith(':') or ': ' in prop:
# Syntax is "<scope>: [prop]" -- if the optional prop exists,
# it becomes the first rule with no suffix
scope, unscoped_value = prop.split(':', 1)
scope = scope.rstrip()
unscoped_value = unscoped_value.lstrip()
return BlockScopeHeader(scope, unscoped_value)
else:
return BlockSelectorHeader(prop)
class BlockAtRuleHeader(BlockHeader):
is_atrule = True
def __init__(self, directive, argument):
self.directive = directive
self.argument = argument
def __repr__(self):
return "<%s %r %r>" % (type(self).__name__, self.directive, self.argument)
def render(self):
if self.argument:
return "%s %s" % (self.directive, self.argument)
else:
return self.directive
class BlockSelectorHeader(BlockHeader):
is_selector = True
def __init__(self, selectors):
self.selectors = tuple(selectors)
def __repr__(self):
return "<%s %r>" % (type(self).__name__, self.selectors)
def render(self, sep=', ', super_selector=''):
return sep.join(sort(
super_selector + s.render()
for s in self.selectors
if not s.has_placeholder))
class BlockScopeHeader(BlockHeader):
is_scope = True
def __init__(self, scope, unscoped_value):
self.scope = scope
if unscoped_value:
self.unscoped_value = unscoped_value
else:
self.unscoped_value = None
class UnparsedBlock(object):
"""A Sass block whose contents have not yet been parsed.
At the top level, CSS (and Sass) documents consist of a sequence of blocks.
A block may be a ruleset:
selector { block; block; block... }
Or it may be an @-rule:
@rule arguments { block; block; block... }
Or it may be only a single property declaration:
property: value
pyScss's first parsing pass breaks the document into these blocks, and each
block becomes an instance of this class.
"""
def __init__(self, parent_rule, lineno, prop, unparsed_contents):
self.parent_rule = parent_rule
self.header = BlockHeader.parse(prop, has_contents=bool(unparsed_contents))
# Basic properties
self.lineno = lineno
self.prop = prop
self.unparsed_contents = unparsed_contents
@property
def directive(self):
return self.header.directive
@property
def argument(self):
return self.header.argument
### What kind of thing is this?
@property
def is_atrule(self):
return self.header.is_atrule
@property
def is_scope(self):
return self.header.is_scope
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