Lyth for Visual Studio Code

Support for Lyth, a programming language that compiles to readable Go: all of Go, in fewer lines.

Features

• Syntax highlighting with the same grammar as the Lyth docs, so code reads the same in the editor and on lyth.bkymz.net, including string templates ("hi ${name}") and ```lyth code blocks in Markdown.
• The Lyth language server (lyth lsp), answering from the compiler itself:
  • Lyth's errors and warnings as you type, including the check of the generated Go, with quick fixes from the compiler's suggested edits. On save, go vet's findings on the .lyth lines.
  • Hover with the declaration, its doc comment and the Go it compiles to; Go declarations show their Go doc.
  • Go to definition (also into the Go standard library and modules), type definition, references, highlights, and rename across the module, following what each name resolves to.
  • Completion of members (fields, methods, lyth/coll's extension functions, packages' exports), names in scope and import paths; signature help; document and workspace symbols.
  • Inlay hints with inferred types: x := f(), loop variables, lambda parameters, func f() = ... results.
• Run and test: ▶ Run above func main, ▶ Run Test above each test function of a _test.lyth file, and Run File and Run Tests in Package in the editor's run menu. They run as tasks in the terminal.
• Show Generated Go (the preview button in the editor title): the Go for the current file beside it, updated as you type.
• Tasks for Lyth modules: lyth build, run, test, check and vet under Terminal → Run Task. In tasks.json, use {"type": "lyth", "command": "build", "args": ["./..."]}.
• Snippets: main, func, method, struct, interface, enum, when, for, catch, test, ...

Requirements

Lyth needs Go 1.26 or newer and the lyth command:

brew install lyth-lang/tap/lyth
# or
go install github.com/lyth-lang/lyth/cmd/lyth@latest

If lyth isn't on the PATH (or in Go's bin directory, ~/go/bin), the extension offers to install it with go install. Set lyth.path to use another build, such as one from a checkout of the Lyth repository.

Settings

Restricted Mode

In an untrusted workspace only highlighting and snippets work: the language server and the run commands run the Go toolchain on the code.

Development

The extension lives in editors/vscode-lyth of the Lyth repository. Building and testing it needs Node.js 22 or newer.

npm install
npm run build      # bundles src/ into out/extension.js and writes the grammars
npm test           # grammar tests, then integration tests in VS Code
npm run package    # writes lyth-<version>.vsix

The TextMate grammar is generated from the docs site's (website/src/lyth-grammar.mjs); change it there. Open this folder in VS Code and press F5 to try the extension in a new window. The integration tests download VS Code unless VSCODE_EXECUTABLE points to one, and build lyth from the repository unless LYTH_PATH is set. Grammar tests are in test/grammar, in the vscode-tmgrammar-test format.