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from .ast import AtRule, Declaration, ParseError, QualifiedRule
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from .tokenizer import parse_component_value_list
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def _to_token_iterator(input, skip_comments=False):
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"""Iterate component values out of string or component values iterable.
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:type input: :obj:`str` or :term:`iterable`
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:param input: A string or an iterable of :term:`component values`.
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:type skip_comments: :obj:`bool`
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:param skip_comments: If the input is a string, ignore all CSS comments.
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:returns: An iterator yielding :term:`component values`.
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"""
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# Accept ASCII-only byte strings on Python 2, with implicit conversion.
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if isinstance(input, str):
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input = parse_component_value_list(input, skip_comments)
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return iter(input)
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def _next_significant(tokens):
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"""Return the next significant (neither whitespace or comment) token.
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:type tokens: :term:`iterator`
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:param tokens: An iterator yielding :term:`component values`.
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:returns: A :term:`component value`, or :obj:`None`.
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"""
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for token in tokens:
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if token.type not in ('whitespace', 'comment'):
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return token
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def parse_one_component_value(input, skip_comments=False):
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"""Parse a single :diagram:`component value`.
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This is used e.g. for an attribute value
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referred to by ``attr(foo length)``.
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:type input: :obj:`str` or :term:`iterable`
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:param input: A string or an iterable of :term:`component values`.
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:type skip_comments: :obj:`bool`
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:param skip_comments: If the input is a string, ignore all CSS comments.
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:returns:
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A :term:`component value` (that is neither whitespace or comment),
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or a :class:`~tinycss2.ast.ParseError`.
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"""
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tokens = _to_token_iterator(input, skip_comments)
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first = _next_significant(tokens)
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second = _next_significant(tokens)
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if first is None:
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return ParseError(1, 1, 'empty', 'Input is empty')
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if second is not None:
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return ParseError(
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second.source_line, second.source_column, 'extra-input',
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'Got more than one token')
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else:
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return first
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def parse_one_declaration(input, skip_comments=False):
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"""Parse a single :diagram:`declaration`.
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This is used e.g. for a declaration in an `@supports
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<https://drafts.csswg.org/css-conditional/#at-supports>`_ test.
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:type input: :obj:`str` or :term:`iterable`
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:param input: A string or an iterable of :term:`component values`.
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:type skip_comments: :obj:`bool`
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:param skip_comments: If the input is a string, ignore all CSS comments.
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:returns:
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A :class:`~tinycss2.ast.Declaration`
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or :class:`~tinycss2.ast.ParseError`.
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Any whitespace or comment before the ``:`` colon is dropped.
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"""
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tokens = _to_token_iterator(input, skip_comments)
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first_token = _next_significant(tokens)
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if first_token is None:
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return ParseError(1, 1, 'empty', 'Input is empty')
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return _parse_declaration(first_token, tokens)
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def _parse_declaration(first_token, tokens):
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"""Parse a declaration.
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Consume :obj:`tokens` until the end of the declaration or the first error.
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:type first_token: :term:`component value`
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:param first_token: The first component value of the rule.
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:type tokens: :term:`iterator`
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:param tokens: An iterator yielding :term:`component values`.
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:returns:
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A :class:`~tinycss2.ast.Declaration`
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or :class:`~tinycss2.ast.ParseError`.
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"""
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name = first_token
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if name.type != 'ident':
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return ParseError(name.source_line, name.source_column, 'invalid',
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'Expected <ident> for declaration name, got %s.'
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% name.type)
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colon = _next_significant(tokens)
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if colon is None:
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return ParseError(name.source_line, name.source_column, 'invalid',
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"Expected ':' after declaration name, got EOF")
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elif colon != ':':
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return ParseError(colon.source_line, colon.source_column, 'invalid',
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"Expected ':' after declaration name, got %s."
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% colon.type)
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value = []
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state = 'value'
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for i, token in enumerate(tokens):
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if state == 'value' and token == '!':
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state = 'bang'
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bang_position = i
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elif state == 'bang' and token.type == 'ident' \
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and token.lower_value == 'important':
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state = 'important'
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elif token.type not in ('whitespace', 'comment'):
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state = 'value'
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value.append(token)
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if state == 'important':
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del value[bang_position:]
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return Declaration(name.source_line, name.source_column, name.value,
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name.lower_value, value, state == 'important')
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def _consume_declaration_in_list(first_token, tokens):
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"""Like :func:`_parse_declaration`, but stop at the first ``;``."""
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other_declaration_tokens = []
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for token in tokens:
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if token == ';':
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break
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other_declaration_tokens.append(token)
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return _parse_declaration(first_token, iter(other_declaration_tokens))
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def parse_declaration_list(input, skip_comments=False, skip_whitespace=False):
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"""Parse a :diagram:`declaration list` (which may also contain at-rules).
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This is used e.g. for the :attr:`~tinycss2.ast.QualifiedRule.content`
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of a style rule or ``@page`` rule,
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or for the ``style`` attribute of an HTML element.
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In contexts that don’t expect any at-rule,
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all :class:`~tinycss2.ast.AtRule` objects
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should simply be rejected as invalid.
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:type input: :obj:`str` or :term:`iterable`
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:param input: A string or an iterable of :term:`component values`.
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:type skip_comments: :obj:`bool`
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:param skip_comments:
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Ignore CSS comments at the top-level of the list.
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If the input is a string, ignore all comments.
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:type skip_whitespace: :obj:`bool`
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:param skip_whitespace:
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Ignore whitespace at the top-level of the list.
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Whitespace is still preserved
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in the :attr:`~tinycss2.ast.Declaration.value` of declarations
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and the :attr:`~tinycss2.ast.AtRule.prelude`
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and :attr:`~tinycss2.ast.AtRule.content` of at-rules.
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:returns:
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A list of
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:class:`~tinycss2.ast.Declaration`,
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:class:`~tinycss2.ast.AtRule`,
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:class:`~tinycss2.ast.Comment` (if ``skip_comments`` is false),
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:class:`~tinycss2.ast.WhitespaceToken`
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(if ``skip_whitespace`` is false),
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and :class:`~tinycss2.ast.ParseError` objects
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"""
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tokens = _to_token_iterator(input, skip_comments)
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result = []
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for token in tokens:
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if token.type == 'whitespace':
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if not skip_whitespace:
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result.append(token)
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elif token.type == 'comment':
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if not skip_comments:
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result.append(token)
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elif token.type == 'at-keyword':
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result.append(_consume_at_rule(token, tokens))
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elif token != ';':
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result.append(_consume_declaration_in_list(token, tokens))
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return result
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def parse_one_rule(input, skip_comments=False):
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"""Parse a single :diagram:`qualified rule` or :diagram:`at-rule`.
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This would be used e.g. by `insertRule()
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<https://drafts.csswg.org/cssom/#dom-cssstylesheet-insertrule>`_
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in an implementation of CSSOM.
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:type input: :obj:`str` or :term:`iterable`
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:param input: A string or an iterable of :term:`component values`.
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:type skip_comments: :obj:`bool`
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:param skip_comments:
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If the input is a string, ignore all CSS comments.
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:returns:
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A :class:`~tinycss2.ast.QualifiedRule`,
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:class:`~tinycss2.ast.AtRule`,
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or :class:`~tinycss2.ast.ParseError` objects.
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Any whitespace or comment before or after the rule is dropped.
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"""
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tokens = _to_token_iterator(input, skip_comments)
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first = _next_significant(tokens)
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if first is None:
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return ParseError(1, 1, 'empty', 'Input is empty')
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rule = _consume_rule(first, tokens)
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next = _next_significant(tokens)
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if next is not None:
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return ParseError(
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next.source_line, next.source_column, 'extra-input',
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'Expected a single rule, got %s after the first rule.' % next.type)
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return rule
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def parse_rule_list(input, skip_comments=False, skip_whitespace=False):
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"""Parse a non-top-level :diagram:`rule list`.
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This is used for parsing the :attr:`~tinycss2.ast.AtRule.content`
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of nested rules like ``@media``.
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This differs from :func:`parse_stylesheet` in that
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top-level ``<!--`` and ``-->`` tokens are not ignored.
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:type input: :obj:`str` or :term:`iterable`
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:param input: A string or an iterable of :term:`component values`.
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:type skip_comments: :obj:`bool`
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:param skip_comments:
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Ignore CSS comments at the top-level of the list.
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If the input is a string, ignore all comments.
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:type skip_whitespace: :obj:`bool`
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:param skip_whitespace:
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Ignore whitespace at the top-level of the list.
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Whitespace is still preserved
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in the :attr:`~tinycss2.ast.QualifiedRule.prelude`
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and the :attr:`~tinycss2.ast.QualifiedRule.content` of rules.
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:returns:
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A list of
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:class:`~tinycss2.ast.QualifiedRule`,
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:class:`~tinycss2.ast.AtRule`,
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:class:`~tinycss2.ast.Comment` (if ``skip_comments`` is false),
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:class:`~tinycss2.ast.WhitespaceToken`
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(if ``skip_whitespace`` is false),
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and :class:`~tinycss2.ast.ParseError` objects.
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"""
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tokens = _to_token_iterator(input, skip_comments)
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result = []
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for token in tokens:
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if token.type == 'whitespace':
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if not skip_whitespace:
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result.append(token)
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elif token.type == 'comment':
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if not skip_comments:
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result.append(token)
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else:
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result.append(_consume_rule(token, tokens))
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return result
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def parse_stylesheet(input, skip_comments=False, skip_whitespace=False):
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"""Parse :diagram:`stylesheet` from text.
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This is used e.g. for a ``<style>`` HTML element.
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This differs from :func:`parse_rule_list` in that
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top-level ``<!--`` and ``-->`` tokens are ignored.
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This is a legacy quirk for the ``<style>`` HTML element.
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:type input: :obj:`str` or :term:`iterable`
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:param input: A string or an iterable of :term:`component values`.
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:type skip_comments: :obj:`bool`
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:param skip_comments:
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Ignore CSS comments at the top-level of the stylesheet.
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If the input is a string, ignore all comments.
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:type skip_whitespace: :obj:`bool`
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:param skip_whitespace:
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Ignore whitespace at the top-level of the stylesheet.
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Whitespace is still preserved
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in the :attr:`~tinycss2.ast.QualifiedRule.prelude`
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and the :attr:`~tinycss2.ast.QualifiedRule.content` of rules.
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:returns:
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A list of
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:class:`~tinycss2.ast.QualifiedRule`,
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:class:`~tinycss2.ast.AtRule`,
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:class:`~tinycss2.ast.Comment` (if ``skip_comments`` is false),
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:class:`~tinycss2.ast.WhitespaceToken`
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(if ``skip_whitespace`` is false),
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and :class:`~tinycss2.ast.ParseError` objects.
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"""
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tokens = _to_token_iterator(input, skip_comments)
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result = []
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for token in tokens:
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if token.type == 'whitespace':
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if not skip_whitespace:
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result.append(token)
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elif token.type == 'comment':
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if not skip_comments:
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result.append(token)
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elif token not in ('<!--', '-->'):
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result.append(_consume_rule(token, tokens))
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return result
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def _consume_rule(first_token, tokens):
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"""Parse a qualified rule or at-rule.
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Consume just enough of :obj:`tokens` for this rule.
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:type first_token: :term:`component value`
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:param first_token: The first component value of the rule.
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:type tokens: :term:`iterator`
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:param tokens: An iterator yielding :term:`component values`.
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:returns:
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A :class:`~tinycss2.ast.QualifiedRule`,
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:class:`~tinycss2.ast.AtRule`,
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or :class:`~tinycss2.ast.ParseError`.
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"""
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if first_token.type == 'at-keyword':
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return _consume_at_rule(first_token, tokens)
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if first_token.type == '{} block':
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prelude = []
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block = first_token
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else:
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prelude = [first_token]
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for token in tokens:
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if token.type == '{} block':
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block = token
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break
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prelude.append(token)
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else:
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return ParseError(
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prelude[-1].source_line, prelude[-1].source_column, 'invalid',
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'EOF reached before {} block for a qualified rule.')
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return QualifiedRule(first_token.source_line, first_token.source_column,
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prelude, block.content)
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def _consume_at_rule(at_keyword, tokens):
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"""Parse an at-rule.
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Consume just enough of :obj:`tokens` for this rule.
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:type at_keyword: :class:`AtKeywordToken`
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:param at_keyword: The at-rule keyword token starting this rule.
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:type tokens: :term:`iterator`
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:param tokens: An iterator yielding :term:`component values`.
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:returns:
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A :class:`~tinycss2.ast.QualifiedRule`,
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or :class:`~tinycss2.ast.ParseError`.
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"""
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prelude = []
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content = None
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for token in tokens:
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if token.type == '{} block':
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content = token.content
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break
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elif token == ';':
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break
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prelude.append(token)
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return AtRule(at_keyword.source_line, at_keyword.source_column,
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at_keyword.value, at_keyword.lower_value, prelude, content)
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