Stream: beginners

Topic: Markdown parser and transformer

Jonas Schell (Mar 12 2024 at 22:26):

I want to sneak Roc into the company I work for. Starting with some small scripts for non-critical tasks.
I want to start with a Markdown manipulation script that reads a Markdown file and replaces a section of it with some new content.
Naturally the question came up, what is the state of Markdown in Roc? Do we have any packages that I'm not aware of? I searched the Zulip history and found some attempts by @Luke Boswell , but nothing concrete. I would be grateful if someone could point out something that would be valuable for someone who is about to write a Markdown parser (to do something that is already being done by a regex). :D

Jonas Schell (Mar 12 2024 at 22:28):

I was thinking of parsing the markdown into an AST to manipulate it and then rendering it back to markdown.

Richard Feldman (Mar 12 2024 at 22:46):

that's awesome! :smiley:

Richard Feldman (Mar 12 2024 at 22:48):

I don't know if anyone's written a full markdown parser in pure Roc, but there are several in Elm - e.g. this, this, or the one I think is probably the most battle-tested - and the latter two are written using elm/parser, which someone has ported to Roc (although I'm not sure how battle-tested that port is!)

Jonas Schell (Mar 12 2024 at 23:02):

Thanks for sharing!

Jonas Schell (Mar 12 2024 at 23:04):

Would lukewilliamboswell/roc-parser be a good fit to use instead of ported elm/parser? :thinking:

Jonas Schell (Mar 12 2024 at 23:08):

I don't know much about parsers, so I'm wondering if there's something that disqualifies it from the start.

Richard Feldman (Mar 12 2024 at 23:46):

oh I just suggested that because it might make porting easier

Richard Feldman (Mar 12 2024 at 23:46):

I'd expect either one to work fine!

Luke Boswell (Mar 12 2024 at 23:56):

How much functionality do you need with markdown? Could you do without embedded html? If so I could probably put a Markdown module together pretty quickly, or help you with that using roc-parser.

Luke Boswell (Mar 12 2024 at 23:57):

There has been a start made on xml parsing, but it still needs more love before it could parse html.

Luke Boswell (Mar 12 2024 at 23:58):

Or at least just parse the html into a single HmtlNode or something and leave it untouched.

Jonas Schell (Mar 13 2024 at 19:45):

Thank you for your help. Using html would be cool, but I think your single HtmlNode approach would work for now. :thumbs_up:

Jonas Schell (Mar 13 2024 at 19:48):

I would probably start by looking at Dillon's markdown implementation in elm and try to go from there.

Jonas Schell (Mar 13 2024 at 19:50):

I'll then share my first steps with you, and if you have time to take a look, I'd love to hear your feedback :)

Last updated: Jul 26 2025 at 12:14 UTC