Shelly Shell for VS Code

The extension's internal name is shelly-shell, matching the Rust package. It recognizes .shy files and Shelly shebangs, starts shelly --language-server, and displays semantic highlighting and syntax diagnostics. The server uses the same tokenizer, parser, and semantic classifications as the REPL. There is no separate TextMate grammar. Your VS Code theme chooses the colors.

Requires VS Code 1.140 or later and a Shelly build supporting --language-server (introduced in the shell's 0.5.2 source). The extension does not bundle the shell. On Windows, run it in a WSL workspace with Shelly installed inside WSL. Linux and macOS use their native Shelly executable.

Build and install locally

Build Shelly from the repository root with cargo build --locked. Then:

cd extensions/vscode
npm ci
npm run package
code --install-extension shelly-shell.vsix

Configure the executable in VS Code settings:

{
    "shelly-shell.serverPath": "/absolute/path/to/shelly/target/debug/shelly"
}

The default is shelly on PATH. Absolute paths, ~/ paths, and paths relative to the first workspace folder are supported. The executable must support --language-server; an older installed shell will not. After changing the path, run Shelly: Restart Language Server. The server is launched directly, without another shell. In WSL, SSH, or a container, install the extension in that remote environment and configure a path available there.

In a WSL window, use Preferences: Open Remote Settings (JSON) for the Linux executable path. A newly installed extension may need Developer: Reload Window to refresh its settings schema. Shelly: Restart Language Server starts a new process after changing the path or rebuilding the binary. The extension checks CLI help for --language-server before connecting, so older binaries produce a specific error. The Shelly output channel records the selected executable and startup failures. A release built before server support must be updated manually or replaced in this setting with the current debug binary.

Packaging uses Node.js 22 or later. See publishing instructions for preparing a Marketplace release.

For development, open shelly-shell.code-workspace, build Shelly, and press F5. The workspace launches an Extension Development Host using the debug binary. The Shelly output channel reports startup failures. Set shelly-shell.trace.server to messages or verbose for protocol tracing.

First-version boundaries

Highlighting includes lexical tokens, parser context, declarations, native types and methods, and understood references within the current document. For example, let is an argument in echo let, and references inside interpolated strings are classified without evaluating them. Invalid syntax gets diagnostics; unfinished input gets hints. Clearing or closing a document clears its diagnostics.

The server never executes profiles, RC files, the prelude, imports, or document code. Standard-library and workspace import indexing, completion, hover, navigation, formatting, and type checking are follow-up work. Unknown names do not produce speculative type errors. Source analysis covers up to 1 MiB and 640,000 parser reads per document, with a diagnostic when a limit is reached. Analysis results are cached by document version; stale updates are ignored.