mirror of https://github.com/zulip/zulip.git
239 lines
9.0 KiB
Python
239 lines
9.0 KiB
Python
"""
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CodeHilite Extension for Python-Markdown
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========================================
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Adds code/syntax highlighting to standard Python-Markdown code blocks.
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Copyright 2006-2008 [Waylan Limberg](http://achinghead.com/).
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Project website: <http://packages.python.org/Markdown/extensions/code_hilite.html>
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Contact: markdown@freewisdom.org
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License: BSD (see ../LICENSE.md for details)
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Dependencies:
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* [Python 2.3+](http://python.org/)
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* [Markdown 2.0+](http://packages.python.org/Markdown/)
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* [Pygments](http://pygments.org/)
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"""
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from six import text_type
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from typing import Any, Dict, List, Optional, Tuple, Union
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from xml.etree.ElementTree import ElementTree
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from zerver.lib.str_utils import force_text
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import markdown
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try:
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from pygments import highlight
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from pygments.lexers import get_lexer_by_name, guess_lexer, TextLexer
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from pygments.formatters import HtmlFormatter
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pygments = True
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except ImportError:
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pygments = False
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# ------------------ The Main CodeHilite Class ----------------------
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class CodeHilite(object):
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"""
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Determine language of source code, and pass it into the pygments hilighter.
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Basic Usage:
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>>> code = CodeHilite(src = 'some text')
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>>> html = code.hilite()
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* src: Source string or any object with a .readline attribute.
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* force_linenos: (Boolean) Force line numbering 'on' (True) or 'off' (False).
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If not specified, number lines iff a shebang line is present.
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* guess_lang: (Boolean) Turn language auto-detection 'on' or 'off' (on by default).
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* css_class: Set class name of wrapper div ('codehilite' by default).
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Low Level Usage:
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>>> code = CodeHilite()
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>>> code.src = 'some text' # String or anything with a .readline attr.
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>>> code.linenos = True # True or False; Turns line numbering on or of.
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>>> html = code.hilite()
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"""
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def __init__(self, src=None, force_linenos=None, guess_lang=True,
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css_class="codehilite", lang=None, style='default',
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noclasses=False, tab_length=4):
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# type: (Optional[text_type], Optional[bool], bool, text_type, Optional[text_type], text_type, bool, int) -> None
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self.src = src
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self.lang = lang
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self.linenos = force_linenos
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self.guess_lang = guess_lang
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self.css_class = css_class
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self.style = style
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self.noclasses = noclasses
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self.tab_length = tab_length
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def hilite(self):
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# type: () -> text_type
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"""
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Pass code to the [Pygments](http://pygments.pocoo.org/) highliter with
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optional line numbers. The output should then be styled with css to
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your liking. No styles are applied by default - only styling hooks
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(i.e.: <span class="k">).
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returns : A string of html.
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"""
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self.src = self.src.strip('\n')
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if self.lang is None:
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self._getLang()
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if pygments:
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try:
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lexer = get_lexer_by_name(self.lang)
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except ValueError:
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try:
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if self.guess_lang:
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lexer = guess_lexer(self.src)
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else:
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lexer = TextLexer()
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except ValueError:
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lexer = TextLexer()
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formatter = HtmlFormatter(linenos=bool(self.linenos),
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cssclass=self.css_class,
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style=self.style,
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noclasses=self.noclasses)
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return highlight(self.src, lexer, formatter)
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else:
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# just escape and build markup usable by JS highlighting libs
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txt = self.src.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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classes = []
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if self.lang:
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classes.append('language-%s' % (self.lang,))
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if self.linenos:
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classes.append('linenums')
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class_str = ''
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if classes:
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class_str = ' class="%s"' % ' '.join(classes)
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return '<pre class="%s"><code%s>%s</code></pre>\n'% \
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(self.css_class, class_str, txt)
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def _getLang(self):
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# type: () -> None
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"""
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Determines language of a code block from shebang line and whether said
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line should be removed or left in place. If the sheband line contains a
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path (even a single /) then it is assumed to be a real shebang line and
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left alone. However, if no path is given (e.i.: #!python or :::python)
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then it is assumed to be a mock shebang for language identifitation of a
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code fragment and removed from the code block prior to processing for
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code highlighting. When a mock shebang (e.i: #!python) is found, line
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numbering is turned on. When colons are found in place of a shebang
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(e.i.: :::python), line numbering is left in the current state - off
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by default.
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"""
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import re
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# split text into lines
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lines = self.src.split("\n")
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# pull first line to examine
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fl = lines.pop(0)
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c = re.compile(u'''
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(?:(?:^::+)|(?P<shebang>^[#]!)) # Shebang or 2 or more colons.
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(?P<path>(?:/\\w+)*[/ ])? # Zero or 1 path
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(?P<lang>[\\w+-]*) # The language
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''', re.VERBOSE)
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# search first line for shebang
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m = c.search(fl)
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if m:
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# we have a match
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try:
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self.lang = m.group('lang').lower()
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except IndexError:
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self.lang = None
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if m.group('path'):
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# path exists - restore first line
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lines.insert(0, fl)
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if m.group('shebang') and self.linenos is None:
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# shebang exists - use line numbers
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self.linenos = True
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else:
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# No match
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lines.insert(0, fl)
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self.src = "\n".join(lines).strip("\n")
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# ------------------ The Markdown Extension -------------------------------
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class HiliteTreeprocessor(markdown.treeprocessors.Treeprocessor):
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""" Hilight source code in code blocks. """
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def run(self, root):
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# type: (ElementTree) -> None
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""" Find code blocks and store in htmlStash. """
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blocks = root.getiterator('pre')
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for block in blocks:
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children = block.getchildren()
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tag = force_text(children[0].tag)
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if len(children) == 1 and tag == 'code':
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text = force_text(children[0].text)
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code = CodeHilite(text,
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force_linenos=self.config['force_linenos'],
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guess_lang=self.config['guess_lang'],
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css_class=self.config['css_class'],
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style=self.config['pygments_style'],
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noclasses=self.config['noclasses'],
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tab_length=self.markdown.tab_length)
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placeholder = self.markdown.htmlStash.store(code.hilite(),
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safe=True)
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# Clear codeblock in etree instance
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block.clear()
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# Change to p element which will later
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# be removed when inserting raw html
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block.tag = 'p'
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block.text = placeholder
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class CodeHiliteExtension(markdown.Extension):
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""" Add source code hilighting to markdown codeblocks. """
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def __init__(self, configs):
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# type: (List[Tuple[str, Union[bool, None, text_type]]]) -> None
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# define default configs
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self.config = {
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'force_linenos' : [None, "Force line numbers - Default: detect based on shebang"],
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'guess_lang' : [True, "Automatic language detection - Default: True"],
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'css_class' : ["codehilite",
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"Set class name for wrapper <div> - Default: codehilite"],
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'pygments_style' : ['default', 'Pygments HTML Formatter Style (Colorscheme) - Default: default'],
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'noclasses': [False, 'Use inline styles instead of CSS classes - Default false']
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} # type: Dict[str, List[Any]]
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# Override defaults with user settings
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for key, value in configs:
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# convert strings to booleans
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if value == 'True': value = True
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if value == 'False': value = False
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self.setConfig(key, value)
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def extendMarkdown(self, md, md_globals):
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# type: (markdown.Markdown, Dict[str, Any]) -> None
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""" Add HilitePostprocessor to Markdown instance. """
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hiliter = HiliteTreeprocessor(md)
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hiliter.config = self.getConfigs()
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md.treeprocessors.add("hilite", hiliter, "<inline")
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md.registerExtension(self)
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def makeExtension(configs=None):
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# type: (Optional[List[Tuple[str, Union[bool, None, text_type]]]]) -> CodeHiliteExtension
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return CodeHiliteExtension(configs=configs or [])
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