Pandoc filter which fakes sans and small-caps syntax by overloading link syntax

pandoc-sf-sc.py

#!/usr/bin/env python

"""
Pandoc filter which fakes sans and small-caps syntax through
overloading link syntax. It wraps the text of links with the 
pseudo-urls ``-sf`` and ``-sc`` in HTML spans with the classes
"sans" and "small-caps" or LaTeX ``\textsf{...}`` and ``\textsc{...}``
commands::

    [this is sans text](-sf)
    [this is small-caps text](-sc)

    <p><span class="sans">this is sans text</span>
    <span class="small-caps">this is small-caps text</span></p>

    \\textsf{this is sans text}
    \\textsc{this is small-caps text}

Limitation: you can't have links inside such text, or such text inside link text!
"""

import pandocfilters as pf

wrapper      = lambda f, s: [ pf.RawInline(f, s) ]
span_wrapper = lambda c: [ pf.RawInline('html', r'<span class="{0}">'.format(c)) ]
cmd_wrapper  = lambda c: [ pf.RawInline('latex', r'\{0}{{'.format(c)) ]

wrap = {
    'html': {
        '-sf': span_wrapper('sans'),
        '-sc': span_wrapper('small-caps'),
        'end': wrapper('html', r'</span>'),
    },
    'latex': {
        '-sf': cmd_wrapper('textsf'),
        '-sc': cmd_wrapper('textsc'),
        'end': wrapper('latex', r'}'),
    },
}

def filter_func(key,val,fmt,meta):
    if not fmt in wrap:
        return None
    if 'Link' != key:
        return None
    (attr, content, target) = val
    (url, title) = target
    if not url in wrap[fmt] or 'end' == url:
        return None
    return wrap[fmt][url] + content + wrap[fmt]['end']
    

if __name__ == "__main__":
    pf.toJSONFilter(filter_func)