Pandoc filter to insert todonotes todos without inline latex

todonotes.lua

--[[
See bottom of scrip for license

Usage:

---
header-includes: |
    \usepackage{todonotes}
...

text text text [TODO: todo text goes here] text text.
[TODO:space after the colon is optional]

Here is another one, but with options [TODO: A green note; color=green!40]. Note that the
space after the semicolon is not optional.

This is the list of todos:

[LISTOFTODOS]
]]


local listOfTodosMarker = "[LISTOFTODOS]"
local beginSentinel = "[TODO:"
local optionSentinel = ";"
local endSentinel = "]"
local State = { BEGIN = 0, PARSING = 1, OPTIONS = 2 }

local function ends_with(str, val)
    return str:sub(#str - #val + 1) == val
end

local function starts_with(str, val)
    return str:sub(1, #val) == val
end

local function make_todo(text, options)
    local str = "\\todo"
    if options then
        str = str .. "[" .. options .. "]"
    end
    str = str .. "{" .. text .. "}"
    return pandoc.RawInline("latex", str)
end

local function make_list_of_todos()
    return pandoc.RawInline("latex", "\\listoftodos")
end

local function run_todonotes(para)
    local changed = false
    local state = State.BEGIN
    local currTodo = ""
    local currOptions = ""
    local currStart = 0
    local currEnd = 0
    local function reset()
        currTodo = ""
        currStart = 0
        currEnd = 0
    end

    local function fill_with_space()
        for i = currStart + 1, currEnd do
            para.content[i] = pandoc.Space()
        end
    end

    for idx, inline in pairs(para.content) do
        local text = inline.text
        currEnd = currEnd + 1
        if text then
            if state == State.BEGIN then
                if starts_with(text, beginSentinel) then
                    changed = true
                    currTodo = currTodo .. text:sub(#beginSentinel + 1)
                    if currTodo ~= "" then currTodo = currTodo .. " " end
                    currStart = idx
                    currEnd = idx
                    state = State.PARSING
                elseif text == listOfTodosMarker then
                    changed = true
                    para.content[idx] = make_list_of_todos()
                end
            elseif state == State.PARSING then
                if ends_with(text, endSentinel) then
                    currTodo = currTodo .. text:sub(1, #text - #endSentinel)
                    fill_with_space()
                    para.content[currStart] = make_todo(currTodo)
                    reset()
                    state = State.BEGIN
                elseif ends_with(text, optionSentinel) then
                    currTodo = currTodo .. text:sub(1, #text - #optionSentinel)
                    state = State.OPTIONS
                else
                    currTodo = currTodo .. text .. " "
                end
            elseif state == State.OPTIONS then
                if ends_with(text, endSentinel) then
                    currOptions = currOptions .. text:sub(1, #text - #endSentinel)
                    fill_with_space()
                    para.content[currStart] = make_todo(currTodo, currOptions)
                    reset()
                    state = State.BEGIN
                else
                    currOptions = currOptions .. text .. " "
                end
            else
                error("Unknwon state: " .. tostring(state))
            end
        end
    end
    if changed then return para end
end

return {
    { Para = run_todonotes }
}



--[[
This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or
distribute this software, either in source code form or as a compiled
binary, for any purpose, commercial or non-commercial, and by any
means.

In jurisdictions that recognize copyright laws, the author or authors
of this software dedicate any and all copyright interest in the
software to the public domain. We make this dedication for the benefit
of the public at large and to the detriment of our heirs and
successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
software under copyright law.

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 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.

For more information, please refer to <https://unlicense.org>
]]