92 lines
3.1 KiB
Python
92 lines
3.1 KiB
Python
# Python Markdown
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# A Python implementation of John Gruber's Markdown.
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# Documentation: https://python-markdown.github.io/
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# GitHub: https://github.com/Python-Markdown/markdown/
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# PyPI: https://pypi.org/project/Markdown/
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# Started by Manfred Stienstra (http://www.dwerg.net/).
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# Maintained for a few years by Yuri Takhteyev (http://www.freewisdom.org).
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# Currently maintained by Waylan Limberg (https://github.com/waylan),
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# Dmitry Shachnev (https://github.com/mitya57) and Isaac Muse (https://github.com/facelessuser).
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# Copyright 2007-2023 The Python Markdown Project (v. 1.7 and later)
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# Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
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# Copyright 2004 Manfred Stienstra (the original version)
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# License: BSD (see LICENSE.md for details).
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"""
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Preprocessors work on source text before it is broken down into its individual parts.
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This is an excellent place to clean up bad characters or to extract portions for later
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processing that the parser may otherwise choke on.
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"""
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from __future__ import annotations
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from typing import TYPE_CHECKING, Any
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from . import util
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from .htmlparser import HTMLExtractor
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import re
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if TYPE_CHECKING: # pragma: no cover
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from markdown import Markdown
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def build_preprocessors(md: Markdown, **kwargs: Any) -> util.Registry[Preprocessor]:
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""" Build and return the default set of preprocessors used by Markdown. """
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preprocessors = util.Registry()
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preprocessors.register(NormalizeWhitespace(md), 'normalize_whitespace', 30)
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preprocessors.register(HtmlBlockPreprocessor(md), 'html_block', 20)
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return preprocessors
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class Preprocessor(util.Processor):
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"""
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Preprocessors are run after the text is broken into lines.
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Each preprocessor implements a `run` method that takes a pointer to a
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list of lines of the document, modifies it as necessary and returns
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either the same pointer or a pointer to a new list.
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Preprocessors must extend `Preprocessor`.
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"""
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def run(self, lines: list[str]) -> list[str]:
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"""
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Each subclass of `Preprocessor` should override the `run` method, which
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takes the document as a list of strings split by newlines and returns
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the (possibly modified) list of lines.
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"""
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pass # pragma: no cover
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class NormalizeWhitespace(Preprocessor):
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""" Normalize whitespace for consistent parsing. """
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def run(self, lines: list[str]) -> list[str]:
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source = '\n'.join(lines)
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source = source.replace(util.STX, "").replace(util.ETX, "")
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source = source.replace("\r\n", "\n").replace("\r", "\n") + "\n\n"
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source = source.expandtabs(self.md.tab_length)
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source = re.sub(r'(?<=\n) +\n', '\n', source)
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return source.split('\n')
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class HtmlBlockPreprocessor(Preprocessor):
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"""
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Remove html blocks from the text and store them for later retrieval.
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The raw HTML is stored in the [`htmlStash`][markdown.util.HtmlStash] of the
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[`Markdown`][markdown.Markdown] instance.
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"""
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def run(self, lines: list[str]) -> list[str]:
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source = '\n'.join(lines)
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parser = HTMLExtractor(self.md)
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parser.feed(source)
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parser.close()
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return ''.join(parser.cleandoc).split('\n')
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