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194 lines
8.1 KiB
Python
194 lines
8.1 KiB
Python
4 months ago
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# Fenced Code Extension for Python Markdown
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# =========================================
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# This extension adds Fenced Code Blocks to Python-Markdown.
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# See https://Python-Markdown.github.io/extensions/fenced_code_blocks
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# for documentation.
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# Original code Copyright 2007-2008 [Waylan Limberg](http://achinghead.com/).
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# All changes Copyright 2008-2014 The Python Markdown Project
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# License: [BSD](https://opensource.org/licenses/bsd-license.php)
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"""
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This extension adds Fenced Code Blocks to Python-Markdown.
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See the [documentation](https://Python-Markdown.github.io/extensions/fenced_code_blocks)
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for details.
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"""
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from __future__ import annotations
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from textwrap import dedent
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from . import Extension
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from ..preprocessors import Preprocessor
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from .codehilite import CodeHilite, CodeHiliteExtension, parse_hl_lines
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from .attr_list import get_attrs_and_remainder, AttrListExtension
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from ..util import parseBoolValue
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from ..serializers import _escape_attrib_html
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import re
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from typing import TYPE_CHECKING, Any, Iterable
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if TYPE_CHECKING: # pragma: no cover
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from markdown import Markdown
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class FencedCodeExtension(Extension):
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def __init__(self, **kwargs):
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self.config = {
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'lang_prefix': ['language-', 'Prefix prepended to the language. Default: "language-"']
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}
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""" Default configuration options. """
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super().__init__(**kwargs)
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def extendMarkdown(self, md):
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""" Add `FencedBlockPreprocessor` to the Markdown instance. """
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md.registerExtension(self)
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md.preprocessors.register(FencedBlockPreprocessor(md, self.getConfigs()), 'fenced_code_block', 25)
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class FencedBlockPreprocessor(Preprocessor):
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""" Find and extract fenced code blocks. """
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FENCED_BLOCK_RE = re.compile(
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dedent(r'''
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(?P<fence>^(?:~{3,}|`{3,}))[ ]* # opening fence
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((\{(?P<attrs>[^\n]*)\})| # (optional {attrs} or
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(\.?(?P<lang>[\w#.+-]*)[ ]*)? # optional (.)lang
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(hl_lines=(?P<quot>"|')(?P<hl_lines>.*?)(?P=quot)[ ]*)?) # optional hl_lines)
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\n # newline (end of opening fence)
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(?P<code>.*?)(?<=\n) # the code block
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(?P=fence)[ ]*$ # closing fence
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'''),
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re.MULTILINE | re.DOTALL | re.VERBOSE
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)
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def __init__(self, md: Markdown, config: dict[str, Any]):
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super().__init__(md)
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self.config = config
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self.checked_for_deps = False
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self.codehilite_conf: dict[str, Any] = {}
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self.use_attr_list = False
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# List of options to convert to boolean values
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self.bool_options = [
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'linenums',
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'guess_lang',
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'noclasses',
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'use_pygments'
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]
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def run(self, lines: list[str]) -> list[str]:
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""" Match and store Fenced Code Blocks in the `HtmlStash`. """
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# Check for dependent extensions
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if not self.checked_for_deps:
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for ext in self.md.registeredExtensions:
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if isinstance(ext, CodeHiliteExtension):
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self.codehilite_conf = ext.getConfigs()
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if isinstance(ext, AttrListExtension):
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self.use_attr_list = True
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self.checked_for_deps = True
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text = "\n".join(lines)
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index = 0
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while 1:
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m = self.FENCED_BLOCK_RE.search(text, index)
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if m:
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lang, id, classes, config = None, '', [], {}
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if m.group('attrs'):
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attrs, remainder = get_attrs_and_remainder(m.group('attrs'))
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if remainder: # Does not have correctly matching curly braces, so the syntax is invalid.
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index = m.end('attrs') # Explicitly skip over this, to prevent an infinite loop.
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continue
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id, classes, config = self.handle_attrs(attrs)
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if len(classes):
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lang = classes.pop(0)
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else:
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if m.group('lang'):
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lang = m.group('lang')
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if m.group('hl_lines'):
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# Support `hl_lines` outside of `attrs` for backward-compatibility
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config['hl_lines'] = parse_hl_lines(m.group('hl_lines'))
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# If `config` is not empty, then the `codehighlite` extension
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# is enabled, so we call it to highlight the code
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if self.codehilite_conf and self.codehilite_conf['use_pygments'] and config.get('use_pygments', True):
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local_config = self.codehilite_conf.copy()
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local_config.update(config)
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# Combine classes with `cssclass`. Ensure `cssclass` is at end
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# as Pygments appends a suffix under certain circumstances.
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# Ignore ID as Pygments does not offer an option to set it.
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if classes:
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local_config['css_class'] = '{} {}'.format(
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' '.join(classes),
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local_config['css_class']
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)
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highliter = CodeHilite(
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m.group('code'),
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lang=lang,
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style=local_config.pop('pygments_style', 'default'),
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**local_config
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)
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code = highliter.hilite(shebang=False)
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else:
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id_attr = lang_attr = class_attr = kv_pairs = ''
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if lang:
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prefix = self.config.get('lang_prefix', 'language-')
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lang_attr = f' class="{prefix}{_escape_attrib_html(lang)}"'
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if classes:
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class_attr = f' class="{_escape_attrib_html(" ".join(classes))}"'
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if id:
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id_attr = f' id="{_escape_attrib_html(id)}"'
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if self.use_attr_list and config and not config.get('use_pygments', False):
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# Only assign key/value pairs to code element if `attr_list` extension is enabled, key/value
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# pairs were defined on the code block, and the `use_pygments` key was not set to `True`. The
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# `use_pygments` key could be either set to `False` or not defined. It is omitted from output.
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kv_pairs = ''.join(
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f' {k}="{_escape_attrib_html(v)}"' for k, v in config.items() if k != 'use_pygments'
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)
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code = self._escape(m.group('code'))
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code = f'<pre{id_attr}{class_attr}><code{lang_attr}{kv_pairs}>{code}</code></pre>'
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placeholder = self.md.htmlStash.store(code)
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text = f'{text[:m.start()]}\n{placeholder}\n{text[m.end():]}'
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# Continue from after the replaced text in the next iteration.
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index = m.start() + 1 + len(placeholder)
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else:
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break
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return text.split("\n")
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def handle_attrs(self, attrs: Iterable[tuple[str, str]]) -> tuple[str, list[str], dict[str, Any]]:
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""" Return tuple: `(id, [list, of, classes], {configs})` """
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id = ''
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classes = []
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configs = {}
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for k, v in attrs:
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if k == 'id':
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id = v
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elif k == '.':
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classes.append(v)
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elif k == 'hl_lines':
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configs[k] = parse_hl_lines(v)
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elif k in self.bool_options:
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configs[k] = parseBoolValue(v, fail_on_errors=False, preserve_none=True)
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else:
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configs[k] = v
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return id, classes, configs
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def _escape(self, txt: str) -> str:
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""" basic html escaping """
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txt = txt.replace('&', '&')
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txt = txt.replace('<', '<')
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txt = txt.replace('>', '>')
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txt = txt.replace('"', '"')
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return txt
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def makeExtension(**kwargs): # pragma: no cover
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return FencedCodeExtension(**kwargs)
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