duskmoon_highlight 2.2.1

Tree-sitter parsing and syntax highlighting for Flutter, with bundled native and WebAssembly grammars.

DuskMoon Highlight

Official Tree-sitter parsing for Flutter Markdown and code editors. The package bundles 95 pinned grammars with source, highlight queries and licenses. Native build hooks compile the official Tree-sitter 0.27.1 C runtime; browser builds use the official web-tree-sitter 0.27.1 module and WebAssembly assets. Browser assets are loaded from the application's own package asset bundle.

Requires Dart 3.10 / Flutter 3.38 or newer and a native C/C++ toolchain when building native apps. No grammar downloads, CDN configuration or index.html changes are required by consumers. JavaScript and Flutter Wasm builds use the same grammar assets.

import 'package:duskmoon_highlight/tree_sitter.dart';

await TreeSitterRuntime.ensureInitialized(languages: {'dart'});
final parser = TreeSitterSession(language: 'dart');
try {
  final first = parser.parse('final answer = 42;');
  final edited = parser.parse('final answer = 43;'); // Incremental parse.
  for (final capture in edited.captures) {
    print('${capture.name}: ${edited.source.substring(capture.from, capture.to)}');
  }
} finally {
  parser.dispose();
}

All offsets count UTF-16 code units, matching Dart strings. Each session owns its mutable parser and previous tree; returned syntax snapshots are immutable and survive edits and disposal. Share runtime initialization, create a separate session for each editor, and dispose it when closed.

TreeSitterRuntime.languages lists the shipped grammars. resolveLanguage accepts case-insensitive canonical names and aliases, including js, jsx, py, sh, ts, tsx and c++. HTML/XML, JavaScript/TypeScript/TSX and C/C++ have distinct grammars. An unknown language resolves to null; callers can render its original text without highlighting. See LANGUAGES.md for the complete inventory and migration coverage.

Highlighting uses structural queries and supported text predicates. Local-scope analysis and embedded-language injection are not implemented; for example, a Vue block highlights its outer grammar without recursively parsing script/style contents. Query omissions and transformations are recorded in grammars.json.

Migration from the previous parser

The Highlight, Mode, HighlightRenderer and generated languages/ / styles/ APIs have been removed. Use TreeSitterSession, SyntaxSnapshot and its captures. There is no automatic language detection. Markdown and editor widgets load their web grammars automatically; direct runtime callers must await initialization. The primary package entrypoint also exports the Tree-sitter API.

Maintenance

Source provenance, grammars.json, THIRD_PARTY_NOTICES and THIRD_PARTY_LICENSES record exact revisions, source archive hashes, local patches and license texts. Native runtime and grammar source is included in published packages because hosted consumers compile it through the build hook. Generated parser C files are stored as deterministic gzip files in hosted packages and unpacked into the build output before compilation. Raw sources remain in this repository; no network access is needed to unpack them.

With Python 3, Dart, Tree-sitter CLI 0.26.8 and WASI SDK 29.0 installed:

python3 packages/duskmoon_highlight/tool/grammars.py build-wasm
python3 packages/duskmoon_highlight/tool/grammars.py generate
python3 packages/duskmoon_highlight/tool/grammars.py verify

The build command accepts --tree-sitter /path/to/tree-sitter and --jobs 3. Set TREE_SITTER_WASI_SDK_PATH for a preinstalled WASI SDK. Keep pinned sources, curated queries, source/asset hashes, generated Dart and notices together when updating a grammar. Generated parsers absent from upstream archives are produced with the CLI version recorded in the manifest; their source grammars are retained. The generate command also refreshes the compressed parsers; verify checks that they decode to the exact pinned source bytes.

devenv shell -- bash -c 'cd packages/duskmoon_highlight && flutter analyze --no-pub --fatal-infos'
devenv shell -- bash -c 'cd packages/duskmoon_highlight && flutter test --no-pub'