# -*- coding: utf-8 -*-
"""
.. _SASS Reference:
http://sass-lang.com/documentation/file.SASS_REFERENCE.html#import
Parser
======
Parser is in charge to find every ``@import`` rules in given SASS content.
It has been builded following `SASS Reference`_ about ``@import`` rule.
"""
import re
from boussole.exceptions import InvalidImportRule
[docs]class ScssImportsParser(object):
"""
SCSS parser to find import rules.
This does not support the old SASS syntax (also known as "indented
syntax").
It's a mixin, meaning without own ``__init__`` method so it's should be
safe enough to inherit it from another class.
Attributes:
REGEX_IMPORT_RULE: Compiled regex used to find import rules.
REGEX_COMMENTS: Compiled regex used to find and remove comments.
"""
REGEX_IMPORT_RULE = re.compile(ur'@import\s*(url)?\s*\(?([^;]+?)\)?;',
re.IGNORECASE)
# Second part (for singleline comment) contain a negative lookbehind
# assertion to avoid to match on url protocole (http://) and cause issues
# in parsing
REGEX_COMMENTS = re.compile(r'(/\*.*?\*/)|((?<!(:))//.*?(\n|$))',
re.IGNORECASE | re.DOTALL)
[docs] def strip_quotes(self, content):
"""
Unquote given rule.
Args:
content (str): An import rule.
Raises:
InvalidImportRule: Raise exception if the rule is badly quoted
(not started or not ended quotes).
Returns:
string: The given rule unquoted.
"""
error_msg = "Following rule is badly quoted: {}"
if (content.startswith('"') and content.endswith('"')) or \
(content.startswith("'") and content.endswith("'")):
return content[1:-1]
# Quote starting but not ended
elif (content.startswith('"') and not content.endswith('"')) or \
(content.startswith("'") and not content.endswith("'")):
raise InvalidImportRule(error_msg.format(content))
# Quote ending but not started
elif (not content.startswith('"') and content.endswith('"')) or \
(not content.startswith("'") and content.endswith("'")):
raise InvalidImportRule(error_msg.format(content))
return content
[docs] def filter_rules(self, path):
"""
Lambda to filter items that:
* Starts with http:// or https:// (this for external load only)
* Ends with ".css" (they are not intended to be compiled)
"""
return not(path.startswith('http://') or
path.startswith('https://') or path.endswith('.css'))
[docs] def flatten_rules(self, declarations):
"""
Flatten returned import rules from regex.
Because import rules can contains multiple items in the same rule
(called multiline import rule), the regex ``REGEX_IMPORT_RULE``
return a list of unquoted items for each rule.
Args:
declarations (list): A SCSS source.
Returns:
list: Given SCSS source with all comments removed.
"""
rules = []
for protocole, paths in declarations:
# If there is a protocole (like 'url), drop it
if protocole:
continue
# Unquote and possibly split multiple rule in the same declaration
rules.extend([self.strip_quotes(v.strip())
for v in paths.split(',')])
return filter(self.filter_rules, rules)
[docs] def parse(self, content):
"""
Parse a stylesheet document with a regex (``REGEX_IMPORT_RULE``)
to extract all import rules and return them.
Args:
content (str): A SCSS source.
Returns:
list: Finded paths in import rules.
"""
# Remove all comments before searching for import rules, to not catch
# commented breaked import rules
declarations = self.REGEX_IMPORT_RULE.findall(
self.remove_comments(content)
)
return self.flatten_rules(declarations)