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 ranges, and call 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.