@unabandoned/regexper-parser

Parses a regular expression into an AST, for @unabandoned/regexper-render to draw.

const parser = require('@unabandoned/regexper-parser')

const tree = parser.parse('/ab+|c/gi', { types })

types is required: the parser is generated by canopy, which copies the matching entry of types onto every node it builds, and the grammar labels every rule. Omit it and parsing throws a TypeError from inside the generated parser. getExtensions() in the render package is the set this grammar needs.

The generated parser is committed

regexp.js is generated from regexp.peg, and it is checked in rather than built.

canopy has had no release since May 2023 and depends on handlebars: ">=4.0.0" and nopt: "*" — unbounded ranges on an unmaintained package, which is the shape of dependency this organisation exists to stop carrying. Since the grammar is 62 lines that have not changed since 2022 and the compiler's output is a static artifact, the artifact is what we keep. Nothing installs canopy to build or test this package.

To change the grammar, edit regexp.peg, regenerate, and commit both:

npx --yes [email protected] ./regexp.peg --lang js

Then check the test suite: it reads the node labels out of regexp.peg and asserts they are the set the renderer implements, so a new label fails there rather than inside a consumer.

regexp.min.js — the unpkg and jsdelivr entry point — is still built, by terser, and the suite parses the same expression through both files to confirm they agree.