Create a gist now

Instantly share code, notes, and snippets.

Github Flavored Markdown in Python
import re
from hashlib import md5
def gfm(text):
# Extract pre blocks.
extractions = {}
def pre_extraction_callback(matchobj):
digest = md5(matchobj.group(0)).hexdigest()
extractions[digest] = matchobj.group(0)
return "{gfm-extraction-%s}" % digest
pattern = re.compile(r'<pre>.*?</pre>', re.MULTILINE | re.DOTALL)
text = re.sub(pattern, pre_extraction_callback, text)
# Prevent foo_bar_baz from ending up with an italic word in the middle.
def italic_callback(matchobj):
s = matchobj.group(0)
if list(s).count('_') >= 2:
return s.replace('_', '\_')
return s
text = re.sub(r'^(?! {4}|\t)\w+_\w+_\w[\w_]*', italic_callback, text)
# In very clear cases, let newlines become <br /> tags.
def newline_callback(matchobj):
if len(matchobj.group(1)) == 1:
return matchobj.group(0).rstrip() + ' \n'
else:
return matchobj.group(0)
pattern = re.compile(r'^[\w\<][^\n]*(\n+)', re.MULTILINE)
text = re.sub(pattern, newline_callback, text)
# Insert pre block extractions.
def pre_insert_callback(matchobj):
return '\n\n' + extractions[matchobj.group(1)]
text = re.sub(r'{gfm-extraction-([0-9a-f]{32})\}', pre_insert_callback, text)
return text
# Test suite.
try:
from nose.tools import assert_equal
except ImportError:
def assert_equal(a, b):
assert a == b, '%r != %r' % (a, b)
def test_single_underscores():
"""Don't touch single underscores inside words."""
assert_equal(
gfm('foo_bar'),
'foo_bar',
)
def test_underscores_code_blocks():
"""Don't touch underscores in code blocks."""
assert_equal(
gfm(' foo_bar_baz'),
' foo_bar_baz',
)
def test_underscores_pre_blocks():
"""Don't touch underscores in pre blocks."""
assert_equal(
gfm('<pre>\nfoo_bar_baz\n</pre>'),
'\n\n<pre>\nfoo_bar_baz\n</pre>',
)
def test_pre_block_pre_text():
"""Don't treat pre blocks with pre-text differently."""
a = '\n\n<pre>\nthis is `a\\_test` and this\\_too\n</pre>'
b = 'hmm<pre>\nthis is `a\\_test` and this\\_too\n</pre>'
assert_equal(
gfm(a)[2:],
gfm(b)[3:],
)
def test_two_underscores():
"""Escape two or more underscores inside words."""
assert_equal(
gfm('foo_bar_baz'),
'foo\\_bar\\_baz',
)
def test_newlines_simple():
"""Turn newlines into br tags in simple cases."""
assert_equal(
gfm('foo\nbar'),
'foo \nbar',
)
def test_newlines_group():
"""Convert newlines in all groups."""
assert_equal(
gfm('apple\npear\norange\n\nruby\npython\nerlang'),
'apple \npear \norange\n\nruby \npython \nerlang',
)
def test_newlines_long_group():
"""Convert newlines in even long groups."""
assert_equal(
gfm('apple\npear\norange\nbanana\n\nruby\npython\nerlang'),
'apple \npear \norange \nbanana\n\nruby \npython \nerlang',
)
def test_newlines_list():
"""Don't convert newlines in lists."""
assert_equal(
gfm('# foo\n# bar'),
'# foo\n# bar',
)
assert_equal(
gfm('* foo\n* bar'),
'* foo\n* bar',
)
@jemerick

Thanks for taking time to fix the bugs in my version. I update my gist as well.

@christian-oudard
Owner

This is a fix of a broken port by Greg Brown at http://gregbrown.co.nz/code/githib-flavoured-markdown-python-implementation/

The original Ruby code is at http://gist.github.com/118964

My fixed version also adds the test cases from the Ruby code.

@mvasilkov

See my fork for better regex flags.

@Triavanicus

My fork of a fork from @mvasilkov adds tables, strike, and links without the use of but not exactly in a nice way, but at least it works.. Here is the link to the forked gist

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment