git.scottworley.com Git - paperdoorknob/blob - texfilter.py

   1 # paperdoorknob: Print glowfic
   2 #
   3 # This program is free software: you can redistribute it and/or modify it
   4 # under the terms of the GNU General Public License as published by the
   5 # Free Software Foundation, version 3.
   6
   7 import re
   8
   9 from typing import Callable, List, Tuple
  10
  11
  12 TexFilters: List[Tuple[str, Callable[[bytes], bytes]]] = [
  13     # Work around `Extra }, or forgotten \endgroup.`
  14     ("FixBareNesting", lambda x: re.sub(
  15         b'(^|\n)(\\\\(emph|st){)', b'\\1\\\\hspace{0pt}\\2', x)),
  16     ("UnicodeApprox", lambda x: re.sub('≈'.encode('utf-8'), b'$\\approx$', x)),
  17     ("UnicodeTriangle", lambda x: re.sub('◁'.encode('utf-8'), b'$\\lhd$', x)),
  18 ]
  19
  20
  21 class TexFilterError(Exception):
  22     pass
  23
  24
  25 def ApplyTexFilters(filter_list: str, data: bytes) -> bytes:
  26     for filter_name in filter_list.split(','):
  27         filters = [f for (name, f) in TexFilters if name == filter_name]
  28         if len(filters) == 0:
  29             raise TexFilterError(f"Unknown Tex filter: {filter_name}")
  30         if len(filters) > 1:
  31             raise TexFilterError(
  32                 f"Multiple Tex filters with the same name!?: {filter_name}")
  33         data = filters[0](data)
  34     return data