uiua.nvim

Minimal Neovim support for the Uiua array language.

• Filetype — *.ua → uiua
• Syntax highlighting — glyphs coloured by arity (monadic / dyadic functions, modifiers, stack ops), plus comments, strings, characters and numbers
• Format on save — pipes the buffer through uiua fmt --io, preserving cursor and scroll position
• LSP — attaches the official uiua lsp server for semantic highlighting, hover and diagnostics

Requirements

The uiua binary on $PATH (cargo install uiua). Formatting and the LSP are silently skipped if it is missing.

Installation

With lazy.nvim:

{
  "TomMurray/uiua.nvim",
  ft = "uiua",
  opts = {},
}

The opts table is passed to require("uiua").setup(). For other plugin managers, call it yourself: require("uiua").setup({ ... }).

Options

Defaults shown:

opts = {
  format_on_save = true,  -- run `uiua fmt` before each write
  lsp = true,             -- attach the official `uiua lsp` server
  server = {},            -- extra config merged into vim.lsp.start
                          -- (e.g. on_attach, capabilities, root_dir)
  highlights = true,      -- link uiua's LSP semantic-token types to
                          -- standard highlight groups (see below)
}

Highlighting

Two layers, complementary:

• syntax/uiua.vim — a regex base layer that colours glyphs by arity, comments, strings and numbers. Works instantly and with no uiua binary.
• uiua lsp semantic tokens — a precise overlay that distinguishes noadic / monadic / dyadic / triadic / tetradic functions, modifiers and modules. More accurate and always matches your installed uiua version.

Colourschemes don't style uiua's custom @lsp.type.* groups, so with highlights = true (default) this plugin links them to standard groups (Function, Operator, Keyword, …). Set highlights = false to opt out, or define your own links — default = true means yours always win:

vim.api.nvim_set_hl(0, "@lsp.type.dyadic_function", { fg = "#89b4fa" })

Example — turn off format on save and add an on_attach:

opts = {
  format_on_save = false,
  server = {
    on_attach = function(client, bufnr)
      -- your keymaps …
    end,
  },
}

Commands

• :UiuaFormat — format the current buffer on demand