Using Pegs in Janet

Posted3 months agoActive3 months ago

Bogdanp

55 points

7 comments

articles.inqk.netTechstory

calmpositive

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Janet Programming LanguagePegs (parsing Expression Grammars)Programming

Key topics

Janet Programming Language

Pegs (parsing Expression Grammars)

Programming

The article explains how to use PEGs in Janet, sparking a discussion about their applications and comparisons to other languages.

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Oct 18, 2025 at 8:33 PM EDT
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Discussion (7 comments)

Showing 7 comments

fithisux

3 months ago

2 replies

Are pegs easier for syntax highlighting or LSPs?

conartist6

3 months ago

1 reply

They're not really the same kind of thing. LSP is a carrier format, but it doesn't know or care how you parse things, whether it's with PEGs or an earley parser or shift reduce or whatever

fithisux

3 months ago

Yes I know, but are they making LSP server construction easier?

veqq

3 months ago

https://janetdocs.org/ does (server side) syntax highlighting through hiccup-lexer which converts janet-peg's tokens to hiccup: https://github.com/sogaiu/janet-peg

The LSP used on vscode works with PEGs also: https://github.com/CFiggers/janet-lsp/blob/ca526aee35c60bcf5...

ktpsns

3 months ago

Reminds me of raku (perl6) grammars https://docs.raku.org/language/grammars

abound

3 months ago

For a bit deeper intro to PEGs in Janet, the Janet for Mortals guide [1] is pretty incredible here (and also uses HTML as an example).

[1] https://janet.guide/pegular-expressions/

andersmurphy

3 months ago

The part I really like about pegs in janet is it works on bytes.

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