@cube-drone/marquee-parser

The reference parser for the Marquee markup language: any byte sequence in, one exact AST out, identically across implementations — held to the published conformance vectors alongside its Rust twin (cube-drone-marquee-parser on crates.io).

import { parse } from "@cube-drone/marquee-parser";

const doc = parse("# hello *world*\n");
// { type: "document", version: 0, children: [...] }

parse() is total — every input yields a document; the only refusal is an unknown dialect version (UnsupportedVersionError). Malformed constructs become invalid_directive nodes with spec'd reasons; confusing inline input degrades to literal text. Nothing is ever eaten.

For editor tooling there's parseWithPositions(source), returning { doc, spans, source }: the same AST byte-for-byte (positions live in a WeakMap side-table, never on the nodes, so serialization and the wire contract are untouched), with each node mapped to its [start, end) extent in UTF-16 code units over the normalized source (\r\n → \n; the returned source is the string offsets refer to — hand it, not your raw input, to anything consuming the spans). A span covers its construct opener-through-closer, markers included; the interiors of canonicalized text (merged literals, resolved escapes) are covered but not subdivided. Built for CodeMirror decorations; deliberately outside the cross-implementation conformance corpus (see SPEC.md, "Source positions").

Three sharp edges, all consequences of "a span is a source extent":

• slice(span) !== node.value wherever the source is denser than the text — a \*b\* c slices nine characters for a seven-character text node.
• A construct that crosses a line inside a container contains that container's prefix: in > *a\n> b*, the emphasis span slices *a\n> b*, > and all. Range marks are fine; a replace decoration over such a range would swallow the quote marker, so split multi-line ranges per line before replacing.
• Blank lines between blocks belong to no node: coverage has gaps, by design.

You probably want @cube-drone/marquee-markup (batteries included: parse + render + CLI) unless you're building a renderer or tool of your own — in which case the AST contract is specified in SPEC.md, and the language itself in WRITING.md.