Nix Extra

lang.nix adds Nix support through the nil language server with nixfmt formatting. Install nixfmt with Nix itself, or add it to your home-manager packages or a project dev shell:

nix profile install nixpkgs#nixfmt

Enable it

-- ~/.config/blak/lua/blak/user.lua
return {
  extras = {
    enabled = {
      "lang.nix",
    },
  },
}

Or enable it interactively:

:BlakExtras enable lang.nix

What it adds

Surface	Contribution
Treesitter	nix
LSP	nil_ls
Formatting	nixfmt for nix

Mason installs nil for nil_ls, and Blak starts the server once that install succeeds. Mason’s nil package compiles from source, so it needs both cargo and nix on $PATH. Without them, every launch reports failed to install nil_ls and the details are in :MasonLog. Mason’s nixfmt package only ships a linux x64 binary, so Blak does not install it. Until nixfmt is on $PATH, saving a .nix file reports Formatters unavailable for nix file and leaves the buffer as it is.

Format with alejandra instead

To format with alejandra instead of nixfmt, install it (nix profile install nixpkgs#alejandra) and override the formatter:

return {
  extras = { enabled = { "lang.nix" } },
  format = {
    formatters_by_ft = {
      nix = { "alejandra" },
    },
  },
}

Install and verify

:BlakToolsInstall
:BlakTreesitterInstall
:BlakDoctor

Open a .nix file and check :checkhealth vim.lsp for nil_ls.