IDE Setup

Lus has an official extension for VSCode-based editors and a stdio language server that can be integrated into any editor with LSP support.

VSCode-based editors

The Lus extension provides syntax highlighting, diagnostics, code completion, hover information, go-to-definition, references, formatting, and more. It bundles a WASM build of Lus and therefore does not require a local installation of the language to work.

VSCodium, Cursor, and Antigravity

Search for Lus in the extensions panel and install it directly.

Visual Studio Code

Microsoft’s VSCode uses the Visual Studio Marketplace by default, which does not host the Lus extension. You will need to install it manually:

1. Download the latest .vsix file from the Open VSX page.
2. Open VSCode, go to the Extensions panel, click the ... menu, and select Install from VSIX….
3. Select the downloaded .vsix file.

Alternatively, install from the command line (replace version with the version of the downloaded extension):

code --install-extension lus-version.vsix

Each example below requires a local installation of lus and the source code’s repository cloned as to access lus-language.

Neovim

With nvim-lspconfig:

vim.api.nvim_create_autocmd("FileType", {
    pattern = "lus",
    callback = function()
        vim.lsp.start({
            name = "lus",
            cmd = { "lus", "/path/to/lus-language/main.lus" },
            root_dir = vim.fs.dirname(
                vim.fs.find({ ".git" }, { upward = true })[1]
            ),
        })
    end,
})

Helix

In languages.toml:

[[language]]
name = "lus"
scope = "source.lus"
file-types = ["lus"]
language-servers = ["lus-language"]

[language-server.lus-language]
command = "lus"
args = ["/path/to/lus-language/main.lus"]

Sublime Text

With LSP for Sublime Text:

{
  "clients": {
    "lus": {
      "enabled": true,
      "command": ["lus", "/path/to/lus-language/main.lus"],
      "selector": "source.lus"
    }
  }
}

Emacs

With lsp-mode:

(with-eval-after-load 'lsp-mode
  (add-to-list 'lsp-language-id-configuration '(lus-mode . "lus"))
  (lsp-register-client
    (make-lsp-client
      :new-connection (lsp-stdio-connection '("lus" "/path/to/lus-language/main.lus"))
      :activation-fn (lsp-activate-on "lus")
      :server-id 'lus-language)))