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Comment by mingodad | Hacker News Reader

For those that want to explore the grammars listed at https://github.com/tree-sitter/tree-sitter/wiki/List-of-pars... in a more friendly railroad diagram format I made https://mingodad.github.io/plgh/json2ebnf.html that reads the "src/grammar.json" and try it's best to generate an EBNF understood by (IPV6) https://www.bottlecaps.de/rr/ui or (IPV4) https://rr.red-dove.com/ui where we get a nice navigable railroad diagram (see https://github.com/GuntherRademacher/rr for offline usage).

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Impressive! The grammar.json file is just a little bit too underspecced to automate some things. Not to mention it's self-referential. How did you deal with extras and other 'specialisms' that are secretly hidden away in the C-level scanner and so on?

I ask because I wrote Combobulate [1], a structured editing and movement tool for Emacs using TS.

1: https://github.com/mickeynp/combobulate

Also there was several requests to create a more formal grammar to describe the grammars but the tree-sitter developers doesn't like the idea and reject then.

But some people did nice attempts like https://github.com/eatkins/tree-sitter-ebnf-generator that I also adapted and exposed it here https://mingodad.github.io/lua-wasm-playground/ to allow play with it online (select "Tree-sitter-ebnf-generator" from examples then click "Run" to see a "grammar.js" generated from the content in "Input Text (arg[1])").

I've added more non trivial grammars Javascript, Java, Kotlin, PHP, C, CPP, Rust, Ruby, CSS, HTML, Python using a quickjs script to convert "src/grammar.json" to an EBNF understood by https://mingodad.github.io/lua-wasm-playground/ (the script is here https://github.com/mingodad/plgh/blob/main/json2ebnf-lua.js).

I simple ignore then as right now they doesn't seen relevant in most grammars to generate an usable railroad diagram.

Hi, in case you're not already aware of the name clash, there's already a `rr` in the programming world. It's "record and replay": https://rr-project.org/.

Very different, but a very fine tool tool too.

It doesn’t seem like the rr that GP linked to is their own project, just something they’ve found useful.

In any case, in the non-software world, “RR” stands for railroad, as it does in the name of that tool. You can’t own a common two-letter abbreviation.

Awesome!

Just yesterday I started some experiments in that direction, to visualize grammars, but now I can rather do something else ..

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