Editor Setup

Arity ships a language server, started with arity lsp (stdio, JSON-RPC). It offers formatting, diagnostics with quick fixes, hover, completion, signature help, go-to-definition and find-references, rename, document and workspace symbols, semantic tokens, folding and selection ranges, document links, document color swatches, and call and type hierarchy.

Configuration is read from an arity.toml discovered from each file’s directory (see the configuration reference).

VS Code/Positron

Install the Arity extension from the VS Code Marketplace or Open VSX. It bundles the arity binary (falling back to a download) and starts the language server automatically for R files. Editors that support VS Code extensions, such as Positron, work the same way.

Neovim

With nvim-lspconfig installed, register arity as a server for R files:

vim.lsp.config("arity", {
  cmd = { "arity", "lsp" },
  filetypes = { "r" },
  root_markers = { "arity.toml", "DESCRIPTION", ".git" },
})
vim.lsp.enable("arity")

Format on save (optional):

vim.api.nvim_create_autocmd("BufWritePre", {
  pattern = "*.R",
  callback = function() vim.lsp.buf.format() end,
})

Helix

In ~/.config/helix/languages.toml:

[language-server.arity]
command = "arity"
args = ["lsp"]

[[language]]
name = "r"
language-servers = ["arity"]
formatter = { command = "arity", args = ["format"] }
auto-format = true

Other editors

Any LSP-capable editor can use arity by launching arity lsp over stdio for the r language. Point your client’s R language-server command at arity with the lsp argument.