Editor Setup

Fatou ships a language server (fatou lsp, stdio JSON-RPC) that already advertises document formatting and pushes parse diagnostics. This guide wires it into your editor so you can format Julia buffers and see parse errors inline.

Coverage is growing construct by construct; constructs without a formatting rule yet are left byte-identical, so formatting is always safe to run.

Prerequisites

Install Fatou (see Getting Started) and make sure the fatou binary is on your PATH, or note its absolute path.

Neovim

Neovim 0.11+ (built-in `vim.lsp.config`)

Add to your config (e.g. init.lua or a file under lua/):

vim.lsp.config("fatou", {
  cmd = { "fatou", "lsp" },              -- or the absolute path to the binary
  filetypes = { "julia" },
  root_markers = { "Project.toml", "JuliaProject.toml", ".git" },
})
vim.lsp.enable("fatou")

Format on save:

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

Older Neovim (autocmd + `vim.lsp.start`)

vim.api.nvim_create_autocmd("FileType", {
  pattern = "julia",
  callback = function(args)
    vim.lsp.start({
      name = "fatou",
      cmd = { "fatou", "lsp" },
      root_dir = vim.fs.root(args.buf, { "Project.toml", "JuliaProject.toml", ".git" }),
    })
  end,
})

Try it

Open a .jl file containing x=1, then run :lua vim.lsp.buf.format() (or just save with the autocmd above). It becomes x = 1. Parse errors, if any, appear as diagnostics (:lua vim.diagnostic.open_float()).

Notes

The server uses full-document sync and full-document formatting today; range formatting (textDocument/rangeFormatting) is on the roadmap.
Multiple formatters? vim.lsp.buf.format({ name = "fatou" }) forces Fatou even if another Julia LSP is attached.

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