Lua filter for abbreviations ignores abbreviations followed by punctuation

[Nerithi]

Following the instructions here, I created a Lua filter for Pandoc to automatically expand my abbreviations. My Pandoc version is 3.8.2.1.

local abbreviations = {
  ["AI"] = "Artificial Intelligence",
  ["ML"] = "Machine Learning"
}

function Str(element)
  local replacement = abbreviations[element.text]
  if replacement then
    return pandoc.Str(replacement)
  end
end

In the MWE below, the expansion happens with the abbreviation AI in the heading and the abbreviation ML in the sentence preceded and followed by a space. The abbreviation does, however, not get expanded when the sentence ends with “AI” followed by a punctuation mark.

---
title: Abbreviations expansion not working
---

# A heading with the abbreviation AI

This text is about AI. It is about ML and other technologies in general.

The expectation would be that the output generated shows “This text is about Artificial Intelligence.” Instead, it remains “This text is about AI.”

While I understand that this probably happens because AI. is a different string to AI by itself, I’m not familiar with Lua and this is a very useful function that I would really like to use, as I have a very long list of abbreviations that I use frequently. I’ve looked into patterns in Lua to get it to ignore potential following punctuation characters, but unfortunately couldn’t figure out how to modify the code/function so it works.

Any help, and, if you can spare the time, an explanation so I understand what’s happening would be greatly appreciated.

[jgm]

Use pandoc -t native to see what the parse tree looks like: this is what the Lua filter is iterating over.

echo "This text is about AI." | pandoc -t native

I think you'll then see why the filter above is too simple.

You can use Lua's pattern matching and substituting functions to do this more reliably. (Note especially that you can pass a table in as a parameter to string.gsub!)

[badumont]

You may use here the functions string.match and/or string.gsub. More generally, if you wish to write Lua filters, it is advisable to learn the basics of Lua (see https://lua.org/docs.html). Personally, I would recommend the book Programming in Lua. It takes some time (not so much actually), but it is very rewarding.