Gregorio (GABC/NABC) — VS Code Extension

Note

AI-Assisted Development

This project is developed, fully or in part, with LLM/generative AI assistance. All LLM-proposed changes go through human review and local testing before being committed.

If you object to software built with generative AI assistance, we respect your opinion and regret we cannot meet your expectations. In that case, we kindly recommend exploring alternative solutions. If you know of any, feel free to open an issue — we'll be happy to include them in our documentation.

Adds support for GABC/NABC (Gregorian chant notation) files to Visual Studio Code.

This is the VS Code counterpart of zed-gregorio and gregorio.nvim, sharing the same ecosystem: the tree-sitter-gregorio grammar and the gregorio-lsp language server.

Features

• Syntax highlighting — A TextMate grammar provides instant, dependency-free highlighting for GABC headers, pitches, clefs, neumes, bars, alterations, style tags, NABC notation, and comments.
• Semantic highlighting (tree-sitter) — On top of the TextMate baseline, a semantic layer powered by tree-sitter-gregorio understands the code's structure, including the GABC/NABC block alternation governed by the nabc-lines header. When the tree-sitter grammar is unavailable, a built-in tokenizer reproduces the same nabc-lines-aware alternation so the feature always works.
• LaTeX embedding — TeX code inside <v>…</v> tags and verbatim attributes ([nv:…], [gv:…], [ev:…]) is highlighted as LaTeX.
• Language server — Diagnostics, hover, completion, document symbols, and document formatting via gregorio-lsp (formatting uses the embedded grefmt engine).
• Editing commands
  • Shift Notes Up / Down (Ctrl+Alt+Up / Ctrl+Alt+Down) — transpose note letters diatonically, wrapping cyclically. With nabc-lines, only GABC segments are transposed; NABC segments are preserved.
  • Fill Empty Note Groups (Ctrl+Alt+L) — fill empty () groups with the last pitch of the preceding group.
  • Convert Ligatures ↔ <sp> Tags — swap æ/ǽ/œ for their <sp> tags.
• Snippets — Header templates (GABC and NABC), markup tags, divisiones, and common response markings.

Requirements

Syntax highlighting works out of the box. For language-server features (diagnostics, hover, completion, formatting), install gregorio-lsp:

cargo install --git https://github.com/AISCGre-BR/gregorio-lsp \
  --tag v0.9.0 --bin gregorio-lsp

Make sure ~/.cargo/bin (or wherever the binary lands) is on your PATH, or set gregorio.languageServer.path to its absolute location.

Commands

Command	Default keybinding
Gregorio: Shift Notes Up	Ctrl+Alt+Up
Gregorio: Shift Notes Down	Ctrl+Alt+Down
Gregorio: Fill Empty Note Groups	Ctrl+Alt+L
Gregorio: Convert Ligatures to <sp> Tags	—
Gregorio: Convert <sp> Tags to Ligatures	—
Gregorio: Restart Language Server	—

All editing commands operate on the current selection, or on the whole chant body (everything after %%) when there is no selection. The header is never modified.

Settings

Setting	Default	Description
gregorio.languageServer.enabled	true	Enable gregorio-lsp.
gregorio.languageServer.path	gregorio-lsp	Path to the server binary.
gregorio.languageServer.formatting.maxLineWidth	80	Max characters per notation line.
gregorio.languageServer.formatting.breakAfterClef	false	Break after each clef.
gregorio.languageServer.formatting.breakAfterBar	false	Break after each bar.
gregorio.semanticHighlighting.enabled	true	Enable tree-sitter semantic highlighting.

Format a document with Format Document (Shift+Alt+F) or enable format on save for GABC:

"[gabc]": { "editor.formatOnSave": true }

Semantic highlighting and the tree-sitter grammar

The semantic layer prefers the compiled tree-sitter-gregorio WASM grammar, whose external scanner resolves the GABC/NABC alternation per the nabc-lines header. Build the grammar and bundle it with:

npm install
npm run build:wasm   # requires the tree-sitter CLI + Emscripten/Docker

This produces parser/tree-sitter-gregorio.wasm (pinned to grammar v0.5.2, matching zed-gregorio / gregorio.nvim). If the grammar is absent, the extension falls back to the built-in nabc-lines-aware tokenizer.

Development

npm install
npm run watch     # bundle with esbuild in watch mode
# Press F5 in VS Code to launch the Extension Development Host
npm run compile   # type-check
npm test          # unit tests for the GABC transforms
npm run package   # build a .vsix

License

MIT — Copyright (c) 2026 AISCGre Brasil. See LICENSE.

The extension icon is a recolored version of the King David illustration from the Gregorio Project.