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Python Markdown: Regexp problem in 'spantable.py' (Python Markdown 2.6.11)
As I noted in my original entry on issues with spantable.py,
the version of Markdown installed using pip differs between Python 2 and
Python 3: the Python 2 version is more up to date. This creates two issues when
trying to use spantables in Python 2:
- The
cell.get()method inxml.etree.elementtreedoesn’t support thedefaultkeyword parameter - The newer Markdown changed the way inline processors work.
I solved the first issue last week, by working around the fact the XML code in
Python 2 is missing a feature. The spantables module now works with Markdown
2.6.7 in both Python 2 and Python 3, but I now have a problem in Markdown 2.6.11:
File "/home/brian/projects/python/markdown_extensions/spantables.py", line 37, in <module> from markdown.inlinepatterns import BacktickPattern, BACKTICK_RE ImportError: Failed loading extension "markdown_extensions.spantables".
The BacktickPattern name is not exported from the inlinepatterns module in
the newer Markdown. In addition, the pattern is 2.6.11 is more complex:
Markdown 2.6.7: BACKTICK_RE = r'(?<!\\)(`+)(.+?)(?<!`)\2(?!`)' Markdown 2.6.11: BACKTICK_RE = r'(?:(?<!\\)((?:\\{2})+)(?=`+)|(?<!\\)(`+)(.+?)(?<!`)\2(?!`))'
And therein seems to be the problem: although I haven’t analysed it closely, I suspect it’s possible for the new regexp to return only three fields instead of 4. So I added a check for that.
Original:
groups = match.groups() delim = groups[1] # the code block delimeter (ie 1 or more backticks) row_contents = groups[2] # the text contained inside the code block i += match.start(4) # jump pointer to the beginning of the rest of the text (group #4) element = delim + row_contents + delim # reinstert backticks current += element
Updated:
groups = match.groups() delim = groups[1] # the code block delimeter (ie 1 or more backticks) row_contents = groups[2] # the text contained inside the code block # jump pointer to the beginning of the rest of the text (group #4) i += (match.start(4) if len(match.groups()) > 3 else 1) - 1 element = delim + row_contents + delim # reinstert backticks current += element