cm6-lezer-scheme-common-lang

A broad Lezer grammar for Scheme/Guile-ish S-expressions, intended to work “generally well” across many S-expression languages while still capturing a few common Scheme heads like define, define-syntax, define-macro, and syntax-rules.

Design goals

• Prefer parsing most Guile code reasonably well.
• Stay broad enough for many other S-expression dialects.
• No external tokenizers (single grammar file).

Tradeoffs

• #| ... |# comments are supported but not nested (nested block comments require an external tokenizer in Lezer).

Install

npm install cm6-lezer-scheme-common-lang

Usage

import { parser } from "cm6-lezer-scheme-common-lang";

const tree = parser.parse("(define (f x) (list x x))");
console.log(tree.toString());

import { scheme } from "cm6-lezer-scheme-common-lang";
const schemeLangSupport = scheme();

Build from source

If you cloned the repo (or you’re using the zip), install deps and build:

npm install
npm run build

This uses lezer-generator to produce:

• dist/parser.js
• dist/parser.terms.js

Lezer CLI behavior is documented in the Lezer guide. (It writes both output and terms files when -o is provided.)

Notable tokens / nodes

• SigilParenStart, SigilBracketStart, SigilBraceStart

  • Catch an edge-case where n characters are glued to an opening delimiter, like foo( or #hash[.

• DefineForm, DefineSyntaxForm, DefineMacroForm, SyntaxRulesForm

  • Recognize lists whose head is define, define-syntax, define-macro, syntax-rules.

License

MIT