Arandu Language Support

This extension adds support for the Arandu programming language to VS Code.

The supported operating systems, protocol features and known limitations are published in the LSP and editor support matrix.

Features

• Syntax Highlighting: Basic offline highlighting via TextMate grammar and full, precise syntax coloring via LSP Semantic Tokens.
• Auto-completion: Smart suggestions for language keywords, module paths, and symbols.
• Signature Help: Inline parameter help for functions and methods.
• Go to Definition: Quickly navigate to the definition of types, functions, and variables.
• Diagnostics: Real-time error and warning reporting directly in the editor.
• Document Formatting: Canonical formatting with minimal edits. Manual formatting is available immediately; format-on-save is opt-in.

Requirements

Release VSIX packages embed the arandu-lsp language server binary for the host platform, so installed builds need no separate SDK setup. For development from this repository the server must be compiled:

cargo build -p arandu_lsp

Running & Developing Locally

To load and run this extension locally for testing or development:

1. Open the editors/vscode directory in VS Code.
2. Run npm install and npm run compile to build the TypeScript code (or use the helper script ./build.sh).
3. Press F5 (or go to Run and Debug -> select Launch Extension). This opens a new "Extension Development Host" VS Code window.
4. In the new window, open any folder containing Arandu files (e.g., examples/stable/syntax).
5. Open any .aru file. The extension will automatically locate the compiled arandu-lsp binary from your target/debug/ directory and activate.

Configuration

You can customize the extension via your VS Code Settings:

• arandu.server.path: Absolute path to the arandu-lsp executable. If null, the extension looks up the binary in this order: the workspace's/repository's target/{release,debug} directory, the arandu-lsp server bundled in the VSIX (bin/), and finally the PATH. The resolved binary is validated with --version before the server starts.
• arandu.trace.server: Log detail level for tracing communication between VS Code and the server (off, messages, or verbose).

Formatting on save is intentionally disabled by default. Enable it only for Arandu files with:

"[arandu]": {
    "editor.defaultFormatter": "arandu.arandu-lang",
    "editor.formatOnSave": true
}

Troubleshooting

The Arandu status item reports whether the language server is starting, indexing, ready, restarting, missing, or stopped. Workspace indexing is also reported through VS Code's native progress UI. Select the status item, or run Arandu: Show Language Server Logs, to open the server log.

Transient crashes are restarted automatically up to three times in a rolling three-minute window. After a repeated crash loop, automatic recovery stops so it cannot consume resources indefinitely. Inspect the log and choose Restart Server, or run Arandu: Restart Language Server, when the underlying issue has been corrected.