third_party/markdown/extensions/fenced_code.py

   1 # markdown is released under the BSD license
   2 # Copyright 2007, 2008 The Python Markdown Project (v. 1.7 and later)
   3 # Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
   4 # Copyright 2004 Manfred Stienstra (the original version)
   5 #
   6 # All rights reserved.
   7 #
   8 # Redistribution and use in source and binary forms, with or without
   9 # modification, are permitted provided that the following conditions are met:
  10 #
  11 # *   Redistributions of source code must retain the above copyright
  12 #     notice, this list of conditions and the following disclaimer.
  13 # *   Redistributions in binary form must reproduce the above copyright
  14 #     notice, this list of conditions and the following disclaimer in the
  15 #     documentation and/or other materials provided with the distribution.
  16 # *   Neither the name of the <organization> nor the
  17 #     names of its contributors may be used to endorse or promote products
  18 #     derived from this software without specific prior written permission.
  19 #
  20 # THIS SOFTWARE IS PROVIDED BY THE PYTHON MARKDOWN PROJECT ''AS IS'' AND ANY
  21 # EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  22 # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  23 # DISCLAIMED. IN NO EVENT SHALL ANY CONTRIBUTORS TO THE PYTHON MARKDOWN PROJECT
  24 # BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  25 # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  26 # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  27 # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  28 # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  29 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  30 # POSSIBILITY OF SUCH DAMAGE.
  31
  32
  33 """
  34 Fenced Code Extension for Python Markdown
  35 =========================================
  36
  37 This extension adds Fenced Code Blocks to Python-Markdown.
  38
  39     >>> import markdown
  40     >>> text = '''
  41     ... A paragraph before a fenced code block:
  42     ...
  43     ... ~~~
  44     ... Fenced code block
  45     ... ~~~
  46     ... '''
  47     >>> html = markdown.markdown(text, extensions=['fenced_code'])
  48     >>> print html
  49     <p>A paragraph before a fenced code block:</p>
  50     <pre><code>Fenced code block
  51     </code></pre>
  52
  53 Works with safe_mode also (we check this because we are using the HtmlStash):
  54
  55     >>> print markdown.markdown(text, extensions=['fenced_code'], safe_mode='replace')
  56     <p>A paragraph before a fenced code block:</p>
  57     <pre><code>Fenced code block
  58     </code></pre>
  59
  60 Include tilde's in a code block and wrap with blank lines:
  61
  62     >>> text = '''
  63     ... ~~~~~~~~
  64     ...
  65     ... ~~~~
  66     ... ~~~~~~~~'''
  67     >>> print markdown.markdown(text, extensions=['fenced_code'])
  68     <pre><code>
  69     ~~~~
  70     </code></pre>
  71
  72 Language tags:
  73
  74     >>> text = '''
  75     ... ~~~~{.python}
  76     ... # Some python code
  77     ... ~~~~'''
  78     >>> print markdown.markdown(text, extensions=['fenced_code'])
  79     <pre><code class="python"># Some python code
  80     </code></pre>
  81
  82 Optionally backticks instead of tildes as per how github's code block markdown is identified:
  83
  84     >>> text = '''
  85     ... `````
  86     ... # Arbitrary code
  87     ... ~~~~~ # these tildes will not close the block
  88     ... `````'''
  89     >>> print markdown.markdown(text, extensions=['fenced_code'])
  90     <pre><code># Arbitrary code
  91     ~~~~~ # these tildes will not close the block
  92     </code></pre>
  93
  94 Copyright 2007-2008 [Waylan Limberg](http://achinghead.com/).
  95
  96 Project website: <http://packages.python.org/Markdown/extensions/fenced_code_blocks.html>
  97 Contact: markdown@freewisdom.org
  98
  99 License: BSD (see ../docs/LICENSE for details)
 100
 101 Dependencies:
 102 * [Python 2.4+](http://python.org)
 103 * [Markdown 2.0+](http://packages.python.org/Markdown/)
 104 * [Pygments (optional)](http://pygments.org)
 105
 106 """
 107
 108 from __future__ import absolute_import
 109 from __future__ import unicode_literals
 110 from . import Extension
 111 from ..preprocessors import Preprocessor
 112 from .codehilite import CodeHilite, CodeHiliteExtension
 113 import re
 114
 115 # Global vars
 116 FENCED_BLOCK_RE = re.compile( \
 117     r'(?P<fence>^(?:~{3,}|`{3,}))[ ]*(\{?\.?(?P<lang>[a-zA-Z0-9_+-]*)\}?)?[ ]*\n(?P<code>.*?)(?<=\n)(?P=fence)[ ]*$',
 118     re.MULTILINE|re.DOTALL
 119     )
 120 CODE_WRAP = '<pre><code%s>%s</code></pre>'
 121 LANG_TAG = ' class="%s"'
 122
 123 class FencedCodeExtension(Extension):
 124
 125     def extendMarkdown(self, md, md_globals):
 126         """ Add FencedBlockPreprocessor to the Markdown instance. """
 127         md.registerExtension(self)
 128
 129         md.preprocessors.add('fenced_code_block',
 130                                  FencedBlockPreprocessor(md),
 131                                  ">normalize_whitespace")
 132
 133
 134 class FencedBlockPreprocessor(Preprocessor):
 135
 136     def __init__(self, md):
 137         super(FencedBlockPreprocessor, self).__init__(md)
 138
 139         self.checked_for_codehilite = False
 140         self.codehilite_conf = {}
 141
 142     def run(self, lines):
 143         """ Match and store Fenced Code Blocks in the HtmlStash. """
 144
 145         # Check for code hilite extension
 146         if not self.checked_for_codehilite:
 147             for ext in self.markdown.registeredExtensions:
 148                 if isinstance(ext, CodeHiliteExtension):
 149                     self.codehilite_conf = ext.config
 150                     break
 151
 152             self.checked_for_codehilite = True
 153
 154         text = "\n".join(lines)
 155         while 1:
 156             m = FENCED_BLOCK_RE.search(text)
 157             if m:
 158                 lang = ''
 159                 if m.group('lang'):
 160                     lang = LANG_TAG % m.group('lang')
 161
 162                 # If config is not empty, then the codehighlite extension
 163                 # is enabled, so we call it to highlite the code
 164                 if self.codehilite_conf:
 165                     highliter = CodeHilite(m.group('code'),
 166                             linenums=self.codehilite_conf['linenums'][0],
 167                             guess_lang=self.codehilite_conf['guess_lang'][0],
 168                             css_class=self.codehilite_conf['css_class'][0],
 169                             style=self.codehilite_conf['pygments_style'][0],
 170                             lang=(m.group('lang') or None),
 171                             noclasses=self.codehilite_conf['noclasses'][0])
 172
 173                     code = highliter.hilite()
 174                 else:
 175                     code = CODE_WRAP % (lang, self._escape(m.group('code')))
 176
 177                 placeholder = self.markdown.htmlStash.store(code, safe=True)
 178                 text = '%s\n%s\n%s'% (text[:m.start()], placeholder, text[m.end():])
 179             else:
 180                 break
 181         return text.split("\n")
 182
 183     def _escape(self, txt):
 184         """ basic html escaping """
 185         txt = txt.replace('&', '&amp;')
 186         txt = txt.replace('<', '&lt;')
 187         txt = txt.replace('>', '&gt;')
 188         txt = txt.replace('"', '&quot;')
 189         return txt
 190
 191
 192 def makeExtension(configs=None):
 193     return FencedCodeExtension(configs=configs)