Lily# VS Code Extension

Version 0.4.0 — the bundled language server and the lysc compiler carry the same number. See the changelog for what is in this release.

Language support for Lily# music notation files (.lys).

Features

Editor Features

Semantic Token Colors

The extension provides custom semantic highlighting:

• Pitches (c, d, e, f, g, a, b): Teal
• Articulations (@staccato, @accent): Yellow
• Dynamics (\p, \f, \ff): Purple

Colors can be customized in settings.

Requirements

None. Each platform's package bundles its own .NET runtime, so nothing has to be installed alongside it — install the extension, open a .lys file, and the language server starts.

(Building from source needs the .NET 10 SDK and Node.js 18+.)

Installation

From VS Code

Open the Extensions view (Ctrl+Shift+X / Cmd+Shift+X), search for Lily#, and install yotsuda.lilysharp. Then open any .lys file. VS Code picks the package built for your platform; nothing else is needed.

From a .vsix

Download the .vsix from Releases, then Extensions view → … → Install from VSIX…, or:

code --install-extension lilysharp-*.vsix

From Source

1. Build the LSP server:

   cd ../..
   dotnet build LilySharp.Lsp
   

2. Build the extension:

   npm install
   npm run compile
   

3. Option A - Development:

   • Open VS Code in this folder
   • Press F5 to launch Extension Development Host

4. Option B - Install locally:

   # Create VSIX package
   npm install -g vsce
   vsce package
   
   # Install the generated .vsix file
   code --install-extension lilysharp-*.vsix
   

Configuration

Configure the path to the language server in VS Code settings:

{
    "lilysharp.serverPath": "/path/to/lilysharp-lsp"
}

If not set, the extension looks for lilysharp-lsp in PATH.

Usage

1. Create a file with .lys extension
2. Start typing Lily# notation
3. Use Ctrl+Space for completion suggestions
4. Hover over elements for documentation
5. Press Ctrl+Shift+O to jump to a symbol, or open the Outline view in the Explorer sidebar for the score structure
6. Use F12 to go to variable definition
7. Use Shift+Alt+F to format document
8. Open the preview (Ctrl+Shift+V), then hold Alt+P to hear the note under the caret, or press Alt+M to play the measure the caret is in (the preview panel is the synth)

Example

title "Example"
tempo 120
time 4/4
key c major

// A reusable phrase, referenced by its bare name.
phrase theme { c4 d e f | g2 g | }

part melody { clef treble }
section Main { melody { theme } }
form main { Main }
score main { staff melody }

Troubleshooting

Language server not starting

1. Check the Output panel (View → Output → Lily# Language Server) — the first lines name the server it chose and how it launched it.
2. Enable tracing: set lilysharp.trace.server to verbose
3. Built from source? A plain dotnet publish is framework-dependent, so that server runs via dotnet and needs the .NET 10 runtime on PATH (dotnet --list-runtimes should list a Microsoft.NETCore.App 10.*). Released packages are self-contained and do not. Check lilysharp.serverPath if you set it.

No syntax highlighting

1. Ensure file has .lys extension
2. Check that the extension is activated (look for Lily# in status bar)

Development

Build

npm install
npm run compile

Watch Mode

npm run watch

Debug

1. Open this folder in VS Code
2. Press F5 to launch Extension Development Host
3. Set breakpoints in TypeScript files

License

GPL-3.0-or-later. The extension bundles the Lily# language server, the Emmentaler music font (GPL/OFL dual license) and MIT-licensed libraries; see LICENSE and THIRD-PARTY-NOTICES in the repository.

Corresponding source. This extension and the language server it bundles are built from https://github.com/yotsuda/LilySharp; the complete corresponding source for a published version is the tagged commit it was built from.

LilyPond. Lily# is an independent project, not affiliated with or endorsed by the LilyPond project. Parts of its engraving engine are ported from LilyPond (GPL v3 or later) and carry its copyright notices; the full list is in LILYPOND-ATTRIBUTION.