#!/usr/bin/env python3
# vim:fileencoding=utf-8
__license__ = 'GPL v3'
__copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
from tinycss.css21 import CSS21Parser
from tinycss.parsing import remove_whitespace, split_on_comma, ParseError
from polyglot.builtins import error_message
class MediaQuery:
__slots__ = 'media_type', 'expressions', 'negated'
def __init__(self, media_type='all', expressions=(), negated=False):
self.media_type = media_type
self.expressions = expressions
self.negated = negated
def __repr__(self):
return '<MediaQuery type=%s negated=%s expressions=%s>' % (
self.media_type, self.negated, self.expressions)
def __eq__(self, other):
return self.media_type == getattr(other, 'media_type', None) and \
self.negated == getattr(other, 'negated', None) and \
self.expressions == getattr(other, 'expressions', None)
class MalformedExpression(Exception):
def __init__(self, tok, msg):
Exception.__init__(self, msg)
self.tok = tok
class CSSMedia3Parser(CSS21Parser):
''' Parse media queries as defined by the CSS 3 media module '''
def parse_media(self, tokens, errors):
if not tokens:
return [MediaQuery('all')]
queries = []
for part in split_on_comma(remove_whitespace(tokens)):
negated = False
media_type = None
expressions = []
try:
for i, tok in enumerate(part):
if i == 0 and tok.type == 'IDENT':
val = tok.value.lower()
if val == 'only':
continue # ignore leading ONLY
if val == 'not':
negated = True
continue
if media_type is None and tok.type == 'IDENT':
media_type = tok.value
continue
elif media_type is None:
media_type = 'all'
if tok.type == 'IDENT' and tok.value.lower() == 'and':
continue
if not tok.is_container:
raise MalformedExpression(tok, 'expected a media expression not a %s' % tok.type)
if tok.type != '(':
raise MalformedExpression(tok, 'media expressions must be in parentheses not %s' % tok.type)
content = remove_whitespace(tok.content)
if len(content) == 0:
raise MalformedExpression(tok, 'media expressions cannot be empty')
if content[0].type != 'IDENT':
raise MalformedExpression(content[0], 'expected a media feature not a %s' % tok.type)
media_feature, expr = content[0].value, None
if len(content) > 1:
if len(content) < 3:
raise MalformedExpression(content[1], 'malformed media feature definition')
if content[1].type != ':':
raise MalformedExpression(content[1], 'expected a :')
expr = content[2:]
if len(expr) == 1:
expr = expr[0]
elif len(expr) == 3 and (expr[0].type, expr[1].type, expr[1].value, expr[2].type) == (
'INTEGER', 'DELIM', '/', 'INTEGER'):
# This should really be moved into token_data, but
# since RATIO is not part of CSS 2.1 and does not
# occur anywhere else, we special case it here.
r = expr[0]
r.value = (expr[0].value, expr[2].value)
r.type = 'RATIO'
r._as_css = expr[0]._as_css + expr[1]._as_css + expr[2]._as_css
expr = r
else:
raise MalformedExpression(expr[0], 'malformed media feature definition')
expressions.append((media_feature, expr))
except MalformedExpression as err:
errors.append(ParseError(err.tok, error_message(err)))
media_type, negated, expressions = 'all', True, ()
queries.append(MediaQuery(media_type or 'all', expressions=tuple(expressions), negated=negated))
return queries
Mini Shell