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270 lines
9.6 KiB
270 lines
9.6 KiB
"""
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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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See <https://Python-Markdown.github.io/extensions/code_hilite>
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for documentation.
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Original code Copyright 2006-2008 [Waylan Limberg](http://achinghead.com/).
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All changes Copyright 2008-2014 The Python Markdown Project
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License: [BSD](https://opensource.org/licenses/bsd-license.php)
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"""
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from . import Extension
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from ..treeprocessors import Treeprocessor
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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
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from pygments.formatters import get_formatter_by_name
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pygments = True
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except ImportError:
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pygments = False
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def parse_hl_lines(expr):
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"""Support our syntax for emphasizing certain lines of code.
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expr should be like '1 2' to emphasize lines 1 and 2 of a code block.
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Returns a list of ints, the line numbers to emphasize.
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"""
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if not expr:
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return []
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try:
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return list(map(int, expr.split()))
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except ValueError:
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return []
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# ------------------ The Main CodeHilite Class ----------------------
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class CodeHilite:
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"""
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Determine language of source code, and pass it into 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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* linenums: (Boolean) Set line numbering to 'on' (True),
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'off' (False) or 'auto'(None). Set to 'auto' by default.
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* guess_lang: (Boolean) Turn language auto-detection
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'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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* hl_lines: (List of integers) Lines to emphasize, 1-indexed.
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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 # 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, linenums=None, guess_lang=True,
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css_class="codehilite", lang=None, style='default',
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noclasses=False, tab_length=4, hl_lines=None, use_pygments=True):
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self.src = src
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self.lang = lang
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self.linenums = linenums
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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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self.hl_lines = hl_lines or []
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self.use_pygments = use_pygments
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def hilite(self):
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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._parseHeader()
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if pygments and self.use_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 = get_lexer_by_name('text')
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except ValueError:
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lexer = get_lexer_by_name('text')
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formatter = get_formatter_by_name('html',
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linenos=self.linenums,
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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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hl_lines=self.hl_lines,
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wrapcode=True)
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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.linenums:
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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 _parseHeader(self):
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"""
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Determines language of a code block from shebang line and whether the
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said line should be removed or left in place. If the sheband line
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contains a path (even a single /) then it is assumed to be a real
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shebang line and left alone. However, if no path is given
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(e.i.: #!python or :::python) then it is assumed to be a mock shebang
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for language identification of a code fragment and removed from the
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code block prior to processing for code highlighting. When a mock
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shebang (e.i: #!python) is found, line numbering is turned on. When
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colons are found in place of a shebang (e.i.: :::python), line
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numbering is left in the current state - off by default.
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Also parses optional list of highlight lines, like:
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:::python hl_lines="1 3"
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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(r'''
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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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\s* # Arbitrary whitespace
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# Optional highlight lines, single- or double-quote-delimited
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(hl_lines=(?P<quot>"|')(?P<hl_lines>.*?)(?P=quot))?
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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 self.linenums is None and m.group('shebang'):
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# Overridable and Shebang exists - use line numbers
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self.linenums = True
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self.hl_lines = parse_hl_lines(m.group('hl_lines'))
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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(Treeprocessor):
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""" Hilight source code in code blocks. """
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def code_unescape(self, text):
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"""Unescape code."""
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text = text.replace("&", "&")
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text = text.replace("<", "<")
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text = text.replace(">", ">")
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return text
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def run(self, root):
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""" Find code blocks and store in htmlStash. """
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blocks = root.iter('pre')
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for block in blocks:
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if len(block) == 1 and block[0].tag == 'code':
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code = CodeHilite(
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self.code_unescape(block[0].text),
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linenums=self.config['linenums'],
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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.md.tab_length,
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use_pygments=self.config['use_pygments']
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)
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placeholder = self.md.htmlStash.store(code.hilite())
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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(Extension):
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""" Add source code hilighting to markdown codeblocks. """
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def __init__(self, **kwargs):
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# define default configs
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self.config = {
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'linenums': [None,
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"Use lines numbers. True=yes, False=no, None=auto"],
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'guess_lang': [True,
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"Automatic language detection - Default: True"],
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'css_class': ["codehilite",
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"Set class name for wrapper <div> - "
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"Default: codehilite"],
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'pygments_style': ['default',
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'Pygments HTML Formatter Style '
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'(Colorscheme) - Default: default'],
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'noclasses': [False,
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'Use inline styles instead of CSS classes - '
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'Default false'],
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'use_pygments': [True,
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'Use Pygments to Highlight code blocks. '
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'Disable if using a JavaScript library. '
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'Default: True']
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}
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super().__init__(**kwargs)
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def extendMarkdown(self, md):
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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.register(hiliter, 'hilite', 30)
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md.registerExtension(self)
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def makeExtension(**kwargs): # pragma: no cover
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return CodeHiliteExtension(**kwargs)
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