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from __future__ import absolute_import
from __future__ import print_function
import six
import logging
from scss.cssdefs import _has_placeholder_re
from scss.types import Undefined
log = logging.getLogger(__name__)
def normalize_var(name):
if isinstance(name, six.string_types):
return name.replace('_', '-')
else:
return name
class VariableScope(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):
self.maps = [dict()] + list(maps)
def __repr__(self):
return "<VariableScope(%s)>" % (', '.join(repr(map) for map in self.maps),)
def __getitem__(self, key):
for map in self.maps:
if key in map:
return map[key]
raise KeyError(key)
def __setitem__(self, key, value):
for map in self.maps:
if key in map:
map[key] = value
return
self.maps[0][key] = value
def new_child(self):
return VariableScope(*self.maps)
class Namespace(object):
"""..."""
def __init__(self, variables=None, functions=None, mixins=None):
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 = VariableScope()
else:
self._functions = VariableScope(functions._functions)
self._mixins = VariableScope()
@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()
else:
self._variables = VariableScope(other._variables for other in others)
self._functions = VariableScope(other._functions for other in others)
self._mixins = VariableScope(other._mixins for other in others)
return self
def derive(self):
return type(self).derive_from(self)
def variable(self, name, throw=False):
name = normalize_var(name)
try:
return self._variables[name]
except KeyError:
if throw:
raise
log.error("Undefined variable '%s'", name)
return Undefined()
def set_variable(self, name, value):
name = normalize_var(name)
assert not (isinstance(value, six.string_types) and value.startswith('$'))
#assert isinstance(value, Value)
self._variables[name] = value
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._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._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, unparsed_contents=None, dependent_rules=None,
options=None, properties=None,
namespace=None,
lineno=0, extends_selectors=frozenset(),
ancestry=None):
self.source_file = source_file
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 dependent_rules is None:
self.dependent_rules = set()
else:
self.dependent_rules = dependent_rules
if properties is None:
self.properties = []
else:
self.properties = properties
self.retval = None
if ancestry is None:
self.ancestry = []
else:
self.ancestry = ancestry
@property
def selectors(self):
# TEMPORARY
if self.ancestry and self.ancestry[-1].is_selector:
return frozenset(self.ancestry[-1].selectors)
else:
return frozenset()
@selectors.setter
def selectors(self, value):
for header in reversed(self.ancestry):
if header.is_selector:
header.selectors |= value
return
else:
# TODO media
break
self.ancestry.append(BlockSelectorHeader(value))
@property
def file_and_line(self):
"""Returns 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):
"""Returns 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 self.ancestry:
header = self.ancestry[-1]
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(),
)
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):
# Simple pre-processing
if prop.startswith('+'):
# Expand '+' at the beginning of a rule as @include
prop = '@include ' + prop[1:]
# TODO what is this, partial sass syntax?
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>" % (self.__class__.__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 = selectors
def __repr__(self):
return "<%s %r>" % (self.__class__.__name__, self.selectors)
def render(self, sep=', ', super_selector=''):
return sep.join(sorted(
super_selector + s
for s in self.selectors
if not _has_placeholder_re.search(s)))
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)
# 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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