Fun (FLS) for VS Code

Official VS Code support for the Fun language. This extension provides syntax highlighting and connects VS Code to the fls language server.

Features

• Syntax highlighting for .fn files
• Language Server support via fls (hover, completion, diagnostics, go-to-definition, formatting, etc. as provided by fls)
• Output channel: Fun Language Server (useful for debugging startup issues)

Requirements

You need the Fun tooling installed:

• fls language server
• fun compiler (optional but recommended; used by fls for deeper analysis)

By default the extension will try, in order:

1. Workspace-local binaries: zig-out/bin/fls(.exe) and zig-out/bin/fun(.exe)
2. Your system PATH (e.g. fls, fun)

Getting Started

1. Install the extension.
2. Open a .fn file.
3. If the server doesn’t start, open View → Output and select Fun Language Server.

Settings

These settings live under Settings → Extensions → Fun:

• fun.fls.path
  • Path to the fls executable.
  • Default: fls (falls back to zig-out/bin/fls when available)
• fun.fls.funPath
  • Optional path to the fun executable.
  • When set to a valid executable, it is passed to fls via the FLS_FUN_PATH environment variable.

Notes:

• Settings support ${workspaceFolder} / ${workspaceRoot}.
• On Windows, %VAR% environment variables inside paths are expanded (best-effort).

Commands

Open the Command Palette and run:

• Fun: Restart Language Server
• Fun: Show Language Server Output

Troubleshooting

No hover / completions / diagnostics

• Verify fls is found:
  • Either ensure it’s on PATH, or set fun.fls.path to the full path.
• If you’re building Fun from source, ensure zig-out/bin exists (or point settings at the built executables).

Standard library isn’t found

• The extension attempts to derive FUN_STDLIB_DIR from the directory containing fls / fun.
• Check the Fun Language Server output for the resolved paths.

Developing This Extension

From this folder (editors/vscode):

1. npm install
2. npm run compile
3. Press F5 in VS Code (Extension Development Host)

Packaging a .vsix:

npm install
npm run package
code --install-extension fun-language-*.vsix

See CONTRIBUTING.md for repo-wide contribution guidelines.