zulip/zephyr/lib/bugdown/fenced_code.py

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#!/usr/bin/env python
"""
Fenced Code Extension for Python Markdown
=========================================
This extension adds Fenced Code Blocks to Python-Markdown.
>>> import markdown
>>> text = '''
... A paragraph before a fenced code block:
...
... ~~~
... Fenced code block
... ~~~
... '''
>>> html = markdown.markdown(text, extensions=['fenced_code'])
>>> print html
<p>A paragraph before a fenced code block:</p>
<pre><code>Fenced code block
</code></pre>
Works with safe_mode also (we check this because we are using the HtmlStash):
>>> print markdown.markdown(text, extensions=['fenced_code'], safe_mode='replace')
<p>A paragraph before a fenced code block:</p>
<pre><code>Fenced code block
</code></pre>
Include tilde's in a code block and wrap with blank lines:
>>> text = '''
... ~~~~~~~~
...
... ~~~~
... ~~~~~~~~'''
>>> print markdown.markdown(text, extensions=['fenced_code'])
<pre><code>
~~~~
</code></pre>
Language tags:
>>> text = '''
... ~~~~{.python}
... # Some python code
... ~~~~'''
>>> print markdown.markdown(text, extensions=['fenced_code'])
<pre><code class="python"># Some python code
</code></pre>
Optionally backticks instead of tildes as per how github's code block markdown is identified:
>>> text = '''
... `````
... # Arbitrary code
... ~~~~~ # these tildes will not close the block
... `````'''
>>> print markdown.markdown(text, extensions=['fenced_code'])
<pre><code># Arbitrary code
~~~~~ # these tildes will not close the block
</code></pre>
Copyright 2007-2008 [Waylan Limberg](http://achinghead.com/).
Project website: <http://packages.python.org/Markdown/extensions/fenced_code_blocks.html>
Contact: markdown@freewisdom.org
License: BSD (see ../docs/LICENSE for details)
Dependencies:
* [Python 2.4+](http://python.org)
* [Markdown 2.0+](http://packages.python.org/Markdown/)
* [Pygments (optional)](http://pygments.org)
"""
import re
import markdown
from zephyr.lib.bugdown.codehilite import CodeHilite, CodeHiliteExtension
# Global vars
FENCE_RE = re.compile(r'(?P<fence>^(?:~{3,}|`{3,}))[ ]*(\{?\.?(?P<lang>[a-zA-Z0-9_+-]*)\}?)', re.MULTILINE|re.DOTALL)
FENCED_BLOCK_RE = re.compile( \
r'(?P<fence>^(?:~{3,}|`{3,}))[ ]*(\{?\.?(?P<lang>[a-zA-Z0-9_+-]*)\}?)?[ ]*\n(?P<code>.*?)(?<=\n)(?P=fence)[ ]*$',
re.MULTILINE|re.DOTALL
)
# Match an inline code expression in markdown: `x=1` or ``def foo(self): bar`` for example
INLINE_CODE_RE = re.compile(r'(?P<fence>`+).+?(?P=fence)')
CODE_WRAP = '<pre><code%s>%s</code></pre>'
LANG_TAG = ' class="%s"'
class FencedCodeExtension(markdown.Extension):
def extendMarkdown(self, md, md_globals):
""" Add FencedBlockPreprocessor to the Markdown instance. """
md.registerExtension(self)
md.preprocessors.add('fenced_code_block',
FencedBlockPreprocessor(md),
"_begin")
class FencedBlockPreprocessor(markdown.preprocessors.Preprocessor):
def __init__(self, md):
markdown.preprocessors.Preprocessor.__init__(self, md)
self.checked_for_codehilite = False
self.codehilite_conf = {}
def run(self, lines):
""" Match and store Fenced Code Blocks in the HtmlStash. """
# Check for code hilite extension
if not self.checked_for_codehilite:
for ext in self.markdown.registeredExtensions:
if isinstance(ext, CodeHiliteExtension):
self.codehilite_conf = ext.config
break
self.checked_for_codehilite = True
text = "\n".join(lines)
while 1:
m = FENCED_BLOCK_RE.search(text)
if not m:
# If there is an inline code block, skip past it
start = 0
inline = INLINE_CODE_RE.search(text, start)
while inline:
start = inline.end()
inline = INLINE_CODE_RE.search(text, start)
fence = FENCE_RE.search(text, start)
if fence:
# If we found a starting fence but no ending fence,
# then we add a closing fence before the two newlines that
# markdown automatically inserts
if text[-2:] == '\n\n':
text = text[:-2] + '\n' + fence.group('fence') + text[-2:]
else:
text += fence.group('fence')
continue
else:
break
lang = ''
if m.group('lang'):
lang = LANG_TAG % m.group('lang')
# If config is not empty, then the codehighlite extension
# is enabled, so we call it to highlite the code
if self.codehilite_conf:
highliter = CodeHilite(m.group('code'),
force_linenos=self.codehilite_conf['force_linenos'][0],
guess_lang=self.codehilite_conf['guess_lang'][0],
css_class=self.codehilite_conf['css_class'][0],
style=self.codehilite_conf['pygments_style'][0],
lang=(m.group('lang') or None),
noclasses=self.codehilite_conf['noclasses'][0])
code = highliter.hilite()
else:
code = CODE_WRAP % (lang, self._escape(m.group('code')))
placeholder = self.markdown.htmlStash.store(code, safe=True)
text = '%s\n%s\n%s'% (text[:m.start()], placeholder, text[m.end():])
return text.split("\n")
def _escape(self, txt):
""" basic html escaping """
txt = txt.replace('&', '&amp;')
txt = txt.replace('<', '&lt;')
txt = txt.replace('>', '&gt;')
txt = txt.replace('"', '&quot;')
return txt
def makeExtension(configs=None):
return FencedCodeExtension(configs=configs)
if __name__ == "__main__":
import doctest
doctest.testmod()