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
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26# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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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'''
34Smart_Strong Extension for Python-Markdown
35==========================================
36
37This extention adds smarter handling of double underscores within words.
38
39Simple Usage:
40
41    >>> import markdown
42    >>> print markdown.markdown('Text with double__underscore__words.',
43    ...                   extensions=['smart_strong'])
44    <p>Text with double__underscore__words.</p>
45    >>> print markdown.markdown('__Strong__ still works.',
46    ...                   extensions=['smart_strong'])
47    <p><strong>Strong</strong> still works.</p>
48    >>> print markdown.markdown('__this__works__too__.',
49    ...                   extensions=['smart_strong'])
50    <p><strong>this__works__too</strong>.</p>
51
52Copyright 2011
53[Waylan Limberg](http://achinghead.com)
54
55'''
56
57from __future__ import absolute_import
58from __future__ import unicode_literals
59from . import Extension
60from ..inlinepatterns import SimpleTagPattern
61
62SMART_STRONG_RE = r'(?<!\w)(_{2})(?!_)(.+?)(?<!_)\2(?!\w)'
63STRONG_RE = r'(\*{2})(.+?)\2'
64
65class SmartEmphasisExtension(Extension):
66    """ Add smart_emphasis extension to Markdown class."""
67
68    def extendMarkdown(self, md, md_globals):
69        """ Modify inline patterns. """
70        md.inlinePatterns['strong'] = SimpleTagPattern(STRONG_RE, 'strong')
71        md.inlinePatterns.add('strong2', SimpleTagPattern(SMART_STRONG_RE, 'strong'), '>emphasis2')
72
73def makeExtension(configs={}):
74    return SmartEmphasisExtension(configs=dict(configs))
75