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import re
from collections.abc import Iterable
from typing import Optional, Dict, Pattern, Match, List
from sybil import Document, Region, Lexeme
from sybil.parsers.abstract.lexers import BlockLexer, strip_prefix
FENCE = re.compile(r"^(?P<prefix>[ \t]*)(?P<fence>`{3,}|~{3,})", re.MULTILINE)
class RawFencedCodeBlockLexer:
"""
A :class:`~sybil.typing.Lexer` for Markdown fenced code blocks allowing flexible lexing
of the whole `info` line along with more complicated prefixes.
The following lexemes are extracted:
- ``source`` as a :class:`~sybil.Lexeme`.
- any other named groups specified in ``info_pattern`` as :class:`strings <str>`.
:param info_pattern:
a :class:`re.Pattern` to match the `info` line and any required prefix that follows it.
:param mapping:
If provided, this is used to rename lexemes from the keys in the mapping to their
values. Only mapped lexemes will be returned in any :class:`~sybil.Region` objects.
"""
def __init__(
self,
info_pattern: Pattern[str] = re.compile(r'$\n', re.MULTILINE),
mapping: Optional[Dict[str, str]] = None,
) -> None:
self.info_pattern = info_pattern
self.mapping = mapping
@staticmethod
def match_closes_existing(current: Match[str], existing: Match[str]) -> bool:
current_fence = current.group('fence')
existing_fence = existing.group('fence')
same_type = current_fence[0] == existing_fence[0]
okay_length = len(current_fence) >= len(existing_fence)
same_prefix = len(current.group('prefix')) == len(existing.group('prefix'))
return same_type and okay_length and same_prefix
def make_region(
self, opening: Match[str], document: Document, closing: Optional[Match[str]]
) -> Optional[Region]:
if closing is None:
content_end = region_end = len(document.text)
else:
content_end = closing.start()
region_end = closing.end()
content = document.text[opening.end(): content_end]
info = self.info_pattern.match(content)
if info is None:
return None
lexemes = info.groupdict()
lexemes['source'] = Lexeme(
strip_prefix(content[info.end():], opening.group('prefix')),
offset=len(opening.group(0))+info.end(),
line_offset=0,
)
if self.mapping:
lexemes = {dest: lexemes[source] for source, dest in self.mapping.items()}
return Region(opening.start(), region_end, lexemes=lexemes)
def __call__(self, document: Document) -> Iterable[Region]:
open_blocks: List[Match[str]] = []
index = 0
while True:
match = FENCE.search(document.text, index)
if match is None:
break
else:
index = match.end()
# does this fence close any open block?
for i in range(len(open_blocks)):
existing = open_blocks[i]
if self.match_closes_existing(match, existing):
maybe_region = self.make_region(existing, document, match)
if maybe_region is not None:
yield maybe_region
open_blocks = open_blocks[:i]
break
else:
open_blocks.append(match)
if open_blocks:
maybe_region = self.make_region(open_blocks[0], document, closing=None)
if maybe_region is not None:
yield maybe_region
class FencedCodeBlockLexer(RawFencedCodeBlockLexer):
"""
A :class:`~sybil.typing.Lexer` for Markdown fenced code blocks where a language is specified.
:class:`RawFencedCodeBlockLexer` can be used if the whole `info` line, or a more complicated
prefix, is required.
The following lexemes are extracted:
- ``language`` as a :class:`str`.
- ``source`` as a :class:`~sybil.Lexeme`.
:param language:
a :class:`str` containing a regular expression pattern to match language names.
:param mapping:
If provided, this is used to rename lexemes from the keys in the mapping to their
values. Only mapped lexemes will be returned in any :class:`~sybil.Region` objects.
"""
def __init__(self, language: str, mapping: Optional[Dict[str, str]] = None) -> None:
super().__init__(
info_pattern=re.compile(f'(?P<language>{language})$\n', re.MULTILINE),
mapping=mapping,
)
DIRECTIVE_IN_HTML_COMMENT_START = (
r"^(?P<prefix>[ \t]*)<!--+\s*(?:;\s*)?(?P<directive>{directive}):?[ \t]"
r"*(?P<arguments>{arguments})[ \t]*"
r"(?:$\n|(?=--+>))"
)
DIRECTIVE_IN_HTML_COMMENT_END = '(?:(?<=\n){prefix})?--+>'
class DirectiveInHTMLCommentLexer(BlockLexer):
"""
A :class:`~sybil.parsers.abstract.lexers.BlockLexer` for faux directives in
HTML-style Markdown comments such as:
.. code-block:: markdown
<!--- not-really-a-directive: some-argument
Source here...
--->
It extracts the following lexemes:
- ``directive`` as a :class:`str`.
- ``arguments`` as a :class:`str`.
- ``source`` as a :class:`~sybil.Lexeme`.
:param directive:
a :class:`str` containing a regular expression pattern to match directive names.
:param arguments:
a :class:`str` containing a regular expression pattern to match directive arguments.
:param mapping:
If provided, this is used to rename lexemes from the keys in the mapping to their values.
Only mapped lexemes will be returned in any :class:`~sybil.Region` objects.
"""
def __init__(
self, directive: str, arguments: str = '.*?', mapping: Optional[Dict[str, str]] = None
) -> None:
super().__init__(
start_pattern=re.compile(
DIRECTIVE_IN_HTML_COMMENT_START.format(directive=directive, arguments=arguments),
re.MULTILINE
),
end_pattern_template=DIRECTIVE_IN_HTML_COMMENT_END,
mapping=mapping,
)
|
