chore: document preferred language for scanner

[calebdw]

Hello!

This documents that C is the preferred language for external scanners as mentioned in #2897 (comment)

Thanks!

[amaanq]

We might even consider removing c++ support, it's just not needed.

[calebdw]

I'm fine with that, I can update the docs if you want.

[sogaiu]

@amaanq I guess you'd know pretty well about how much C++ use there is in practice given how much rewriting you've done (^^;

Should I check via ts-questions for any remaining scanner.cc files?

[amaanq]

yeah sure I'll check as well and rewrite any that seem to have some sizable usage/relevance, I've just finished rewriting Ruby (last upstream one in c++ that I didn't bother to touch 😆)

[sogaiu]

Some rough results of find | grep | sort | uniq | wc -l:

• grammar.js: 423
• scanner.c: 149
• scanner.cc: 31

Number of repositories: 406

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cc.txt

[amaanq]

A few of those I already sent PRs to rewrite and either the owner just didn't respond or didn't want it (astro, beancount, nickel, cooklang) 🤷
Ikatyang also looks to be very inactive (yaml/vue) 😬

We can keep c++ compilation for now, but in the future I'd like to remove it, and will be removing the mangled c++ symbols that wasm will use for its exported stdlib functions since Ruby no longer needs it.

If the grammars are dead or stubborn, I can always create a fork w/ rewrites for those interested.

I'll submit a PR for TLA+ and Liquidsoap too soon

[amaanq]

Merging for now then I think we can remove C++ support in a month or two