Dodo for Visual Studio Code

Language support for Dodo, using the compiler's built-in dodo lsp language server.

• Syntax highlighting for declarations, types, attributes, strings, byte literals, numeric literals, borrowing, and operators.
• Diagnostics, actionable quick fixes, inferred type inlay hints, completion, hover information, go-to-definition, references, rename, signature help, and document formatting.
• Comment toggling, bracket pairing, indentation, folding, and snippets.
• Unsaved file and untitled buffer support, with compiler target and package-checking settings.

Install

Install Dodo 0.1.4 or newer and ensure dodo --version works. The extension uses an existing compiler; the VSIX does not contain the compiler or LLVM.

Download dodo-vscode-0.1.4.vsix from GitHub Releases, then run:

code --install-extension dodo-vscode-0.1.4.vsix

You can also use Extensions: Install from VSIX... in VS Code and select the downloaded file. Open a .dodo file to activate the extension. VS Code 1.137 or newer is required.

Build from source

With Node.js 22 or newer, run these commands from this repository's root:

cd editor-support/dodo-vscode
npm ci
npm run package
code --install-extension dodo-vscode-0.1.4.vsix

Building the VSIX does not require Rust or LLVM.

Configure the compiler

If Dodo is not on the extension host's PATH, set Dodo: Server Path to the compiler executable. Paths with spaces work without shell quoting:

{
  "dodo.server.path": "${workspaceFolder}/target/debug/dodo"
}

On Windows, use dodo.exe and JSON-escaped backslashes or forward slashes. In SSH, WSL, or a dev container, install the extension and Dodo on that remote host.

Settings

Compiler settings apply to the whole VS Code window. One server handles all workspace folders so unsaved imports remain available across roots. Relative compiler paths and ${workspaceFolder} use the first workspace folder. With no folder open, use an absolute executable path or dodo on PATH. Other variable substitutions and shell commands are not supported.

The server restarts automatically when its executable, enabled state, checking mode, or target changes. For example, match a cross-compilation target with:

{
  "dodo.checkMode": "package",
  "dodo.target": "wasm32-unknown-unknown"
}

Package checking requires the files in each directory to declare the same package. Use the default file mode for folders containing independent example programs.

Use Format Document for the compiler's canonical four-space style. To enable formatting on save explicitly:

{
  "[dodo]": {
    "editor.defaultFormatter": "Jotrorox.dodo-vscode",
    "editor.formatOnSave": true
  }
}

Commands and snippets

The Command Palette provides Dodo: Restart Language Server and Dodo: Show Language Server Output. The output channel includes startup errors. For protocol traces, use Developer: Set Log Level, select Dodo Language Server, and choose Trace. Choose Info to turn tracing off again.

Type a snippet prefix and select it from completion, or use Insert Snippet:

Inlay hints and quick fixes

Inferred local types appear beside their binding names: let answer = 42i32 shows an : i32 hint after answer. Explicit type annotations suppress the corresponding hint. Hints follow unsaved edits and use VS Code's Editor: Inlay Hints: Enabled setting. To enable them specifically for Dodo:

{
  "[dodo]": {
    "editor.inlayHints.enabled": "on"
  }
}

Place the cursor on a diagnostic and open Quick Fix... (Ctrl+. on Windows and Linux, Cmd+. on macOS). For a direct assignment to, or mutable borrow of, an immutable local binding, Make count mutable changes let count = 1 to count := 1. For a missing package qualifier such as math.answer(), Import math inserts the matching import when the server can resolve a public member in a bundled library or nearby local package. Unqualified names require a manual import.

Quick fixes apply normal editor edits, so they can be undone and do not save the file. Diagnostics and hints refresh after the edit. Some diagnostics have no safe automatic fix, and unresolved types have no inlay hint. These features require a compiler build with inlay-hint and code-action support.

Troubleshooting and limits

If the server fails to start, open its output channel and check the executable path. Specify only the compiler executable: the extension adds lsp automatically. After installing or rebuilding Dodo, use Dodo: Restart Language Server.

Highlighting and snippets work without a compiler and in Restricted Mode. The language server starts after the workspace is trusted. It supports file and untitled documents in desktop/remote VS Code; virtual workspace files and a browser-only extension host cannot run the native compiler.

Navigation and rename cover open documents and loaded imports. Bundled library definitions open read-only sources supplied by the running compiler, with hover and navigation available inside them. Imported .dodo files are watched for disk changes: creating, editing, or deleting a dependency refreshes diagnostics and navigation automatically. Unsaved open buffers keep their contents. See the editor guide for the server's current limits.

Develop and test

Open this folder in VS Code, run npm ci, then press F5 to launch an Extension Development Host. The launch configuration builds the extension first. For continuous bundling, run npm run watch; use npm run check to check TypeScript.

npm test
npm run package

npm test checks TypeScript, bundles the extension, and tests the TextMate grammar using VS Code's tokenizer and Oniguruma engine, including the repository examples. The bundle includes its language-client dependencies; packaging excludes source, tests, source maps, and development dependencies.

For a real VS Code and compiler integration test, first build Dodo from the repository root with cargo build --locked --bin dodo, then run here:

npm run test:integration

The runner downloads VS Code 1.137.0 to test the minimum supported version and uses an isolated temporary workspace and profile. It exercises LSP features, including inferred type hints and applying missing-import and mutability quick fixes, plus settings changes, restart, unsaved overlays, untitled buffers, and snippet insertion. Set DODO_TEST_SERVER to an absolute compiler path to use another build, and VSCODE_TEST_VERSION=stable to test current VS Code. Linux needs a display; on a headless machine use xvfb-run -a npm run test:integration.

The extension follows VS Code's language server extension guide. Its highlighting rules follow Dodo's lexer and parser; update the grammar tests when the compiler's syntax changes.

License

BSD-2-Clause, like Dodo.

Printing completions include print, println, and printf. Signature help for printf shows its literal format and heterogeneous args... tail; diagnostics check placeholders and argument types. The printf snippet inserts a checked console call. Braces inside format strings remain string contents during highlighting and document formatting.