pandoc-md-to-html-link-filter.py

# pandoc document JSON structure documentation: https://hackage.haskell.org/package/pandoc-types-1.21/docs/Text-Pandoc-Definition.html#t:Inline
# pandocfilters: https://github.com/jgm/pandocfilters
#
# pandocfilters.Link takes 3 arguments
# I'm not sure why,
# but the pandoc documentation for the JSON structure says "Link" also takes 3 arguments,
# which are "Attr [Inline] Target".
# I think that may be a coincidence.
#
# The second argument, 'value', passed to my function,
# is a list with 3 elements.
# These 3 elements appear to match up with the 3 arguments from the pandoc JSON documentation.
# The third one contains the URL of the item,
# and when I modify that I can change the URL in the output document.

from pandocfilters import toJSONFilter, Link

def md_link_to_html(key, value, format, meta):
    if key == "Link":
        url = value[2][0]
        url = url[:-3] + ".html"
        value[2][0] = url
        Link(value, format, meta)

if __name__ == "__main__":
    toJSONFilter(md_link_to_html)