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# Python Markdown | |
# A Python implementation of John Gruber's Markdown. | |
# Documentation: https://python-markdown.github.io/ | |
# GitHub: https://github.com/Python-Markdown/markdown/ | |
# PyPI: https://pypi.org/project/Markdown/ | |
# Started by Manfred Stienstra (http://www.dwerg.net/). | |
# Maintained for a few years by Yuri Takhteyev (http://www.freewisdom.org). | |
# Currently maintained by Waylan Limberg (https://github.com/waylan), | |
# Dmitry Shachnev (https://github.com/mitya57) and Isaac Muse (https://github.com/facelessuser). | |
# Copyright 2007-2023 The Python Markdown Project (v. 1.7 and later) | |
# Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b) | |
# Copyright 2004 Manfred Stienstra (the original version) | |
# License: BSD (see LICENSE.md for details). | |
""" | |
The block parser handles basic parsing of Markdown blocks. It doesn't concern | |
itself with inline elements such as `**bold**` or `*italics*`, but rather just | |
catches blocks, lists, quotes, etc. | |
The `BlockParser` is made up of a bunch of `BlockProcessors`, each handling a | |
different type of block. Extensions may add/replace/remove `BlockProcessors` | |
as they need to alter how Markdown blocks are parsed. | |
""" | |
from __future__ import annotations | |
import xml.etree.ElementTree as etree | |
from typing import TYPE_CHECKING, Iterable, Any | |
from . import util | |
if TYPE_CHECKING: # pragma: no cover | |
from markdown import Markdown | |
from .blockprocessors import BlockProcessor | |
class State(list): | |
""" Track the current and nested state of the parser. | |
This utility class is used to track the state of the `BlockParser` and | |
support multiple levels if nesting. It's just a simple API wrapped around | |
a list. Each time a state is set, that state is appended to the end of the | |
list. Each time a state is reset, that state is removed from the end of | |
the list. | |
Therefore, each time a state is set for a nested block, that state must be | |
reset when we back out of that level of nesting or the state could be | |
corrupted. | |
While all the methods of a list object are available, only the three | |
defined below need be used. | |
""" | |
def set(self, state: Any): | |
""" Set a new state. """ | |
self.append(state) | |
def reset(self) -> None: | |
""" Step back one step in nested state. """ | |
self.pop() | |
def isstate(self, state: Any) -> bool: | |
""" Test that top (current) level is of given state. """ | |
if len(self): | |
return self[-1] == state | |
else: | |
return False | |
class BlockParser: | |
""" Parse Markdown blocks into an `ElementTree` object. | |
A wrapper class that stitches the various `BlockProcessors` together, | |
looping through them and creating an `ElementTree` object. | |
""" | |
def __init__(self, md: Markdown): | |
""" Initialize the block parser. | |
Arguments: | |
md: A Markdown instance. | |
Attributes: | |
BlockParser.md (Markdown): A Markdown instance. | |
BlockParser.state (State): Tracks the nesting level of current location in document being parsed. | |
BlockParser.blockprocessors (util.Registry): A collection of | |
[`blockprocessors`][markdown.blockprocessors]. | |
""" | |
self.blockprocessors: util.Registry[BlockProcessor] = util.Registry() | |
self.state = State() | |
self.md = md | |
def parseDocument(self, lines: Iterable[str]) -> etree.ElementTree: | |
""" Parse a Markdown document into an `ElementTree`. | |
Given a list of lines, an `ElementTree` object (not just a parent | |
`Element`) is created and the root element is passed to the parser | |
as the parent. The `ElementTree` object is returned. | |
This should only be called on an entire document, not pieces. | |
Arguments: | |
lines: A list of lines (strings). | |
Returns: | |
An element tree. | |
""" | |
# Create an `ElementTree` from the lines | |
self.root = etree.Element(self.md.doc_tag) | |
self.parseChunk(self.root, '\n'.join(lines)) | |
return etree.ElementTree(self.root) | |
def parseChunk(self, parent: etree.Element, text: str) -> None: | |
""" Parse a chunk of Markdown text and attach to given `etree` node. | |
While the `text` argument is generally assumed to contain multiple | |
blocks which will be split on blank lines, it could contain only one | |
block. Generally, this method would be called by extensions when | |
block parsing is required. | |
The `parent` `etree` Element passed in is altered in place. | |
Nothing is returned. | |
Arguments: | |
parent: The parent element. | |
text: The text to parse. | |
""" | |
self.parseBlocks(parent, text.split('\n\n')) | |
def parseBlocks(self, parent: etree.Element, blocks: list[str]) -> None: | |
""" Process blocks of Markdown text and attach to given `etree` node. | |
Given a list of `blocks`, each `blockprocessor` is stepped through | |
until there are no blocks left. While an extension could potentially | |
call this method directly, it's generally expected to be used | |
internally. | |
This is a public method as an extension may need to add/alter | |
additional `BlockProcessors` which call this method to recursively | |
parse a nested block. | |
Arguments: | |
parent: The parent element. | |
blocks: The blocks of text to parse. | |
""" | |
while blocks: | |
for processor in self.blockprocessors: | |
if processor.test(parent, blocks[0]): | |
if processor.run(parent, blocks) is not False: | |
# run returns True or None | |
break | |