Simple lua filter to replace intra-word colons as a degender symbol with * or a configurable marker (like _)

degender.lua

--- Replace intra-word colons with gender star or gap
--
-- Copyright 2022 Frederik Elwert <frederik.elwert@rub.de>
--
-- LICENSE
--
-- Permission is hereby granted, free of charge, to any person obtaining a copy
-- of this software and associated documentation files (the "Software"), to
-- deal in the Software without restriction, including without limitation the
-- rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
-- sell copies of the Software, and to permit persons to whom the Software is
-- furnished to do so, subject to the following conditions:
--
-- The above copyright notice and this permission notice shall be included in
-- all copies or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-- FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
-- IN THE SOFTWARE.

local DEFAULT_DEGENDER_MARKER = '*'
local degender_marker

function split_hyphen(inputstr)
  local sep = ':'
  local t = {}
  for str in string.gmatch(inputstr, '([^'..sep..']+)') do
    table.insert(t, str)
  end
  return t
end

function Meta(meta)
  if meta['degender'] then
    degender_marker = pandoc.utils.stringify(meta['degender'])
  else
    degender_marker = DEFAULT_DEGENDER_MARKER
  end
end

function Str(elem)
  local parts = split_hyphen(elem.text)
  -- if not more than one part, string contains no hyphen, return unchanged.
  if #parts <= 1 then
    return nil
  end
  -- otherwise, replace with degender marker
  local o = {}
  for index, part in ipairs(parts) do
    table.insert(o, pandoc.Str(part))
    if index < #parts then
      table.insert(o, pandoc.Str(degender_marker))
    end
  end
  return o
end

return {{Meta = Meta}, {Str = Str}}

example.md

degender	_

An alle Tester:innen, das ist wichtig: Testen!