mirror of https://github.com/zulip/zulip.git
483 lines
16 KiB
Python
483 lines
16 KiB
Python
"""
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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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>>> import markdown
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>>> text = '''
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... A paragraph before a fenced code block:
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...
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... ~~~
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... Fenced code block
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... ~~~
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... '''
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>>> html = markdown.markdown(text, extensions=['fenced_code'])
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>>> print html
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<p>A paragraph before a fenced code block:</p>
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<pre><code>Fenced code block
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</code></pre>
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Works with safe_mode also (we check this because we are using the HtmlStash):
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>>> print markdown.markdown(text, extensions=['fenced_code'], safe_mode='replace')
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<p>A paragraph before a fenced code block:</p>
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<pre><code>Fenced code block
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</code></pre>
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Include tilde's in a code block and wrap with blank lines:
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>>> text = '''
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... ~~~~~~~~
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...
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... ~~~~
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... ~~~~~~~~'''
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>>> print markdown.markdown(text, extensions=['fenced_code'])
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<pre><code>
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~~~~
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</code></pre>
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Removes trailing whitespace from code blocks that cause horizontal scrolling
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>>> import markdown
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>>> text = '''
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... A paragraph before a fenced code block:
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...
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... ~~~
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... Fenced code block \t\t\t\t\t\t\t
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... ~~~
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... '''
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>>> html = markdown.markdown(text, extensions=['fenced_code'])
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>>> print html
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<p>A paragraph before a fenced code block:</p>
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<pre><code>Fenced code block
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</code></pre>
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Language tags:
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>>> text = '''
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... ~~~~{.python}
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... # Some python code
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... ~~~~'''
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>>> print markdown.markdown(text, extensions=['fenced_code'])
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<pre><code class="python"># Some python code
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</code></pre>
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Copyright 2007-2008 [Waylan Limberg](http://achinghead.com/).
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Project website: <http://packages.python.org/Markdown/extensions/fenced_code_blocks.html>
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Contact: markdown@freewisdom.org
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License: BSD (see ../docs/LICENSE for details)
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Dependencies:
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* [Python 2.4+](http://python.org)
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* [Markdown 2.0+](http://packages.python.org/Markdown/)
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* [Pygments (optional)](http://pygments.org)
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"""
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import re
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from typing import Any, Dict, Iterable, List, Mapping, MutableSequence, Optional
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import markdown
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from django.utils.html import escape
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from lxml import etree
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from markdown.extensions.codehilite import CodeHilite, CodeHiliteExtension
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from pygments.lexers import get_lexer_by_name
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from pygments.util import ClassNotFound
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from zerver.lib.exceptions import MarkdownRenderingException
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from zerver.lib.tex import render_tex
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# Global vars
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FENCE_RE = re.compile("""
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# ~~~ or ```
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(?P<fence>
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^(?:~{3,}|`{3,})
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)
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[ ]* # spaces
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(
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\\{?\\.?
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(?P<lang>
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[a-zA-Z0-9_+-./#]*
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) # "py" or "javascript"
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\\}?
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) # language, like ".py" or "{javascript}"
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[ ]* # spaces
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(
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\\{?\\.?
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(?P<header>
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[^~`]*
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)
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\\}?
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) # header for features that use fenced block header syntax (like spoilers)
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$
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""", re.VERBOSE)
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CODE_WRAP = '<pre><code{}>{}\n</code></pre>'
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LANG_TAG = ' class="{}"'
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def validate_curl_content(lines: List[str]) -> None:
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error_msg = """
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Missing required -X argument in curl command:
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{command}
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""".strip()
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for line in lines:
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regex = r'curl [-](sS)?X "?(GET|DELETE|PATCH|POST)"?'
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if line.startswith('curl'):
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if re.search(regex, line) is None:
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raise MarkdownRenderingException(error_msg.format(command=line.strip()))
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CODE_VALIDATORS = {
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'curl': validate_curl_content,
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}
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class FencedCodeExtension(markdown.Extension):
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def __init__(self, config: Mapping[str, Any] = {}) -> None:
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self.config = {
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'run_content_validators': [
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config.get('run_content_validators', False),
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'Boolean specifying whether to run content validation code in CodeHandler',
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],
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}
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for key, value in config.items():
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self.setConfig(key, value)
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def extendMarkdown(self, md: markdown.Markdown) -> None:
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""" Add FencedBlockPreprocessor to the Markdown instance. """
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md.registerExtension(self)
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processor = FencedBlockPreprocessor(
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md, run_content_validators=self.config['run_content_validators'][0])
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md.preprocessors.register(processor, 'fenced_code_block', 25)
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class BaseHandler:
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def handle_line(self, line: str) -> None:
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raise NotImplementedError()
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def done(self) -> None:
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raise NotImplementedError()
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def generic_handler(processor: Any, output: MutableSequence[str],
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fence: str, lang: str, header: str,
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run_content_validators: bool=False,
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default_language: Optional[str]=None) -> BaseHandler:
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lang = lang.lower()
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if lang in ('quote', 'quoted'):
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return QuoteHandler(processor, output, fence, default_language)
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elif lang == 'math':
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return TexHandler(processor, output, fence)
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elif lang == 'spoiler':
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return SpoilerHandler(processor, output, fence, header)
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else:
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return CodeHandler(processor, output, fence, lang, run_content_validators)
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def check_for_new_fence(processor: Any, output: MutableSequence[str], line: str,
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run_content_validators: bool=False,
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default_language: Optional[str]=None) -> None:
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m = FENCE_RE.match(line)
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if m:
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fence = m.group('fence')
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lang = m.group('lang')
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header = m.group('header')
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if not lang and default_language:
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lang = default_language
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handler = generic_handler(processor, output, fence, lang, header,
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run_content_validators, default_language)
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processor.push(handler)
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else:
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output.append(line)
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class OuterHandler(BaseHandler):
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def __init__(self, processor: Any, output: MutableSequence[str],
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run_content_validators: bool=False,
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default_language: Optional[str]=None) -> None:
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self.output = output
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self.processor = processor
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self.run_content_validators = run_content_validators
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self.default_language = default_language
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def handle_line(self, line: str) -> None:
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check_for_new_fence(self.processor, self.output, line,
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self.run_content_validators, self.default_language)
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def done(self) -> None:
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self.processor.pop()
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class CodeHandler(BaseHandler):
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def __init__(self, processor: Any, output: MutableSequence[str],
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fence: str, lang: str, run_content_validators: bool=False) -> None:
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self.processor = processor
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self.output = output
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self.fence = fence
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self.lang = lang
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self.lines: List[str] = []
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self.run_content_validators = run_content_validators
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def handle_line(self, line: str) -> None:
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if line.rstrip() == self.fence:
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self.done()
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else:
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self.lines.append(line.rstrip())
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def done(self) -> None:
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text = '\n'.join(self.lines)
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# run content validators (if any)
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if self.run_content_validators:
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validator = CODE_VALIDATORS.get(self.lang, lambda text: None)
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validator(self.lines)
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text = self.processor.format_code(self.lang, text)
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text = self.processor.placeholder(text)
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processed_lines = text.split('\n')
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self.output.append('')
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self.output.extend(processed_lines)
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self.output.append('')
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self.processor.pop()
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class QuoteHandler(BaseHandler):
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def __init__(self, processor: Any, output: MutableSequence[str],
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fence: str, default_language: Optional[str]=None) -> None:
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self.processor = processor
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self.output = output
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self.fence = fence
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self.lines: List[str] = []
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self.default_language = default_language
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def handle_line(self, line: str) -> None:
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if line.rstrip() == self.fence:
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self.done()
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else:
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check_for_new_fence(self.processor, self.lines, line, default_language=self.default_language)
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def done(self) -> None:
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text = '\n'.join(self.lines)
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text = self.processor.format_quote(text)
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processed_lines = text.split('\n')
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self.output.append('')
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self.output.extend(processed_lines)
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self.output.append('')
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self.processor.pop()
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class SpoilerHandler(BaseHandler):
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def __init__(self, processor: Any, output: MutableSequence[str],
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fence: str, spoiler_header: str) -> None:
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self.processor = processor
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self.output = output
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self.fence = fence
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self.spoiler_header = spoiler_header
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self.lines: List[str] = []
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def handle_line(self, line: str) -> None:
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if line.rstrip() == self.fence:
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self.done()
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else:
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check_for_new_fence(self.processor, self.lines, line)
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def done(self) -> None:
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if len(self.lines) == 0:
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# No content, do nothing
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return
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else:
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header = self.spoiler_header
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text = '\n'.join(self.lines)
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text = self.processor.format_spoiler(header, text)
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processed_lines = text.split('\n')
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self.output.append('')
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self.output.extend(processed_lines)
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self.output.append('')
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self.processor.pop()
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class TexHandler(BaseHandler):
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def __init__(self, processor: Any, output: MutableSequence[str], fence: str) -> None:
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self.processor = processor
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self.output = output
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self.fence = fence
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self.lines: List[str] = []
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def handle_line(self, line: str) -> None:
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if line.rstrip() == self.fence:
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self.done()
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else:
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self.lines.append(line)
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def done(self) -> None:
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text = '\n'.join(self.lines)
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text = self.processor.format_tex(text)
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text = self.processor.placeholder(text)
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processed_lines = text.split('\n')
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self.output.append('')
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self.output.extend(processed_lines)
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self.output.append('')
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self.processor.pop()
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class FencedBlockPreprocessor(markdown.preprocessors.Preprocessor):
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def __init__(self, md: markdown.Markdown, run_content_validators: bool=False) -> None:
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markdown.preprocessors.Preprocessor.__init__(self, md)
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self.checked_for_codehilite = False
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self.run_content_validators = run_content_validators
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self.codehilite_conf: Dict[str, List[Any]] = {}
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def push(self, handler: BaseHandler) -> None:
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self.handlers.append(handler)
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def pop(self) -> None:
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self.handlers.pop()
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def run(self, lines: Iterable[str]) -> List[str]:
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""" Match and store Fenced Code Blocks in the HtmlStash. """
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output: List[str] = []
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processor = self
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self.handlers: List[BaseHandler] = []
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default_language = None
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try:
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default_language = self.md.zulip_realm.default_code_block_language
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except AttributeError:
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pass
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handler = OuterHandler(processor, output, self.run_content_validators, default_language)
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self.push(handler)
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for line in lines:
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self.handlers[-1].handle_line(line)
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while self.handlers:
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self.handlers[-1].done()
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# This fiddly handling of new lines at the end of our output was done to make
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# existing tests pass. Markdown is just kind of funny when it comes to new lines,
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# but we could probably remove this hack.
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if len(output) > 2 and output[-2] != '':
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output.append('')
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return output
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def format_code(self, lang: str, text: str) -> str:
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if lang:
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langclass = LANG_TAG.format(lang)
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else:
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langclass = ''
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# Check for code hilite extension
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if not self.checked_for_codehilite:
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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.config
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break
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self.checked_for_codehilite = True
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# If config is not empty, then the codehighlite extension
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# is enabled, so we call it to highlite the code
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if self.codehilite_conf:
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highliter = CodeHilite(text,
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linenums=self.codehilite_conf['linenums'][0],
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guess_lang=self.codehilite_conf['guess_lang'][0],
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css_class=self.codehilite_conf['css_class'][0],
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style=self.codehilite_conf['pygments_style'][0],
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use_pygments=self.codehilite_conf['use_pygments'][0],
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lang=(lang or None),
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noclasses=self.codehilite_conf['noclasses'][0])
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code = highliter.hilite().rstrip('\n')
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else:
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code = CODE_WRAP.format(langclass, self._escape(text))
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# To support our "view in playground" feature, the frontend
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# needs to know what Pygments language was used for
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# highlighting this code block. We record this in a data
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# attribute attached to the outer `pre` element.
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# Unfortunately, the pygments API doesn't offer a way to add
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# this, so we need to do it in a post-processing step.
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if lang:
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parsed_code = etree.HTML(code)
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div_tag = parsed_code[0][0]
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# For the value of our data element, we get the lexer
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# subclass name instead of directly using the language,
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# since that canonicalizes aliases (Eg: `js` and
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# `javascript` will be mapped to `JavaScript`).
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try:
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code_language = get_lexer_by_name(lang).name
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except ClassNotFound:
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# If there isn't a Pygments lexer by this name, we
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# still tag it with the user's data-code-language
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# value, since this allows hooking up a "playground"
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# for custom "languages" that aren't known to Pygments.
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#
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# The escaping isn't strictly necessary, in that the
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# characters allowed for language values should all be
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# safe, but doing escaping here makes it easy to
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# reason about.
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code_language = self._escape(lang)
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div_tag.attrib['data-code-language'] = code_language
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# lxml implicitly converts tags like <span></span> into <span/>.
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# Specifying method="c14n" when converting to string prevents that.
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code = etree.tostring(div_tag, method="c14n").decode()
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return code
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def format_quote(self, text: str) -> str:
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paragraphs = text.split("\n\n")
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quoted_paragraphs = []
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for paragraph in paragraphs:
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lines = paragraph.split("\n")
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quoted_paragraphs.append("\n".join("> " + line for line in lines if line != ''))
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return "\n\n".join(quoted_paragraphs)
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def format_spoiler(self, header: str, text: str) -> str:
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output = []
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header_div_open_html = '<div class="spoiler-block"><div class="spoiler-header">'
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end_header_start_content_html = '</div><div class="spoiler-content" aria-hidden="true">'
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footer_html = '</div></div>'
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output.append(self.placeholder(header_div_open_html))
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output.append(header)
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output.append(self.placeholder(end_header_start_content_html))
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output.append(text)
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output.append(self.placeholder(footer_html))
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return "\n\n".join(output)
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def format_tex(self, text: str) -> str:
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paragraphs = text.split("\n\n")
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tex_paragraphs = []
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for paragraph in paragraphs:
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html = render_tex(paragraph, is_inline=False)
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if html is not None:
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tex_paragraphs.append(html)
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else:
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tex_paragraphs.append('<span class="tex-error">' +
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escape(paragraph) + '</span>')
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return "\n\n".join(tex_paragraphs)
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def placeholder(self, code: str) -> str:
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return self.md.htmlStash.store(code)
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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(*args: Any, **kwargs: None) -> FencedCodeExtension:
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return FencedCodeExtension(kwargs)
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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