Neovim: nvim-lsp + elixir

OK, this is something I am really curious about too.

Using terminal Vim 8, not Neovim, and not using the aforementioned plugins, so my post is slightly off-topic, but regarding Elixir language server support I am very happy with my setup, using ALE and ElixirLS. As far as I know, it should work with Neovim too.

How’s 0.5.0?

Never tried the built-in lsp client, but I use ElixirLS with coc (after spending some time with ALE and LanguageClient-neovim) on nvim 0.4.3, if it’s relevant

I have tried it.

I am not sure if NeoVim has implemented enough of the protocol yet. I wasn’t able to get GoToDefinition or FindReferences to work.

Completions with omnifunc seemed to work, but I didn’t try to get it set up with an actual completions plugin (to have it show completions as I type).

Hover documentation was nice, and is presented with a neovim floating window.

For now I stay on stable release and I use vim-lsp. Works ok.

Hey!
I just wanted to mention that nvim-lsp just merged an elixir-ls configuration into master.

So if anybody come here wondering about how to do that, it should be available now.

https://github.com/neovim/nvim-lsp#elixirls

Could someone setup this correctly?

Yes, I use native LSP with elixir-ls

I have this in my lspconfig for elixir.

-- Elixir
require'lspconfig'.elixirls.setup{
  cmd = { vim.loop.os_homedir().."/path/to/elixir-ls/language_server.sh" };
}

I also have these setup:

" LSP
nnoremap <silent> gd <cmd>lua vim.lsp.buf.definition()<CR>
nnoremap <silent> gD <cmd>lua vim.lsp.buf.declaration()<CR>
nnoremap <silent> gr <cmd>lua vim.lsp.buf.references()<CR>
nnoremap <silent> gi <cmd>lua vim.lsp.buf.implementation()<CR>
nnoremap <silent> K <cmd>lua vim.lsp.buf.hover()<CR>
nnoremap <silent> <C-k> <cmd>lua vim.lsp.buf.signature_help()<CR>
nnoremap <silent> [g <cmd>lua vim.lsp.diagnostic.goto_prev()<CR>
nnoremap <silent> ]g <cmd>lua vim.lsp.diagnostic.goto_next()<CR>

command! -nargs=0 Format :lua vim.lsp.buf.formatting()

I am using completion-nvim for my popup menu but have also been playing around with compe

" Use <Tab> and <S-Tab> to navigate through popup menu
inoremap <expr> <Tab>   pumvisible() ? "\<C-n>" : "\<Tab>"
inoremap <expr> <S-Tab> pumvisible() ? "\<C-p>" : "\<S-Tab>"

" Manually trigger completion
imap <silent> <C-Space> <Plug>(completion_trigger)

" Set completeopt to have a better completion experience
set completeopt=menuone,noinsert,noselect

" Avoid showing message extra message when using completion
set shortmess+=c

let g:completion_matching_strategy_list = ['exact', 'substring', 'fuzzy']

Neovim fam! 0.5.0 is officially here!

Hey!

I wanted to setup NeoVim 0.5 with elixir-ls + autocompletion following this article, and the autocompletion is working, I can see NeoVim communicates with the language server, but syntax highlighting for Elixir is not working for some reason. Everything has the same text color. When I tried some random Ruby project, code was syntax highlighted.

Any help would be really appreciated.

Here’s my init.vim file:

call plug#begin('~/.config/nvim/autoload/plugged')

Plug 'neovim/nvim-lspconfig'
Plug 'hrsh7th/nvim-compe'
Plug 'joshdick/onedark.vim'

call plug#end()

lua <<EOF

local lspconfig = require("lspconfig")

-- Neovim doesn't support snippets out of the box, so we need to mutate the
-- capabilities we send to the language server to let them know we want snippets.
local capabilities = vim.lsp.protocol.make_client_capabilities()
capabilities.textDocument.completion.completionItem.snippetSupport = true

-- Setup our autocompletion. These configuration options are the default ones
-- copied out of the documentation.
require "compe".setup {
  enabled = true,
  autocomplete = true,
  debug = false,
  min_length = 1,
  preselect = "disabled",
  throttle_time = 80,
  source_timeout = 200,
  incomplete_delay = 400,
  max_abbr_width = 100,
  max_kind_width = 100,
  max_menu_width = 100,
  documentation = true,
  source = {
    path = true,
    buffer = true,
    calc = true,
    vsnip = true,
    nvim_lsp = true,
    nvim_lua = true,
    spell = true,
    tags = true,
    treesitter = true
  }
}

-------------------------------------

-- A callback that will get called when a buffer connects to the language server.
-- Here we create any key maps that we want to have on that buffer.
local on_attach = function(_, bufnr)
  local function map(...)
    vim.api.nvim_buf_set_keymap(bufnr, ...)
  end
  local map_opts = {noremap = true, silent = true}

  map("n", "df", "<cmd>lua vim.lsp.buf.formatting()<cr>", map_opts)
  map("n", "gd", "<cmd>lua vim.lsp.diagnostic.show_line_diagnostics()<cr>", map_opts)
  map("n", "dt", "<cmd>lua vim.lsp.buf.definition()<cr>", map_opts)
  map("n", "K", "<cmd>lua vim.lsp.buf.hover()<cr>", map_opts)
  map("n", "gD", "<cmd>lua vim.lsp.buf.implementation()<cr>", map_opts)
  map("n", "<c-k>", "<cmd>lua vim.lsp.buf.signature_help()<cr>", map_opts)
  map("n", "1gD", "<cmd>lua vim.lsp.buf.type_definition()<cr>", map_opts)

  -- These have a different style than above because I was fiddling
  -- around and never converted them. Instead of converting them
  -- now, I'm leaving them as they are for this article because this is
  -- what I actually use, and hey, it works ¯\_(ツ)_/¯.
  vim.cmd [[imap <expr> <C-l> vsnip#available(1) ? '<Plug>(vsnip-expand-or-jump)' : '<C-l>']]
  vim.cmd [[smap <expr> <C-l> vsnip#available(1) ? '<Plug>(vsnip-expand-or-jump)' : '<C-l>']]

  vim.cmd [[imap <expr> <Tab> vsnip#jumpable(1) ? '<Plug>(vsnip-jump-next)' : '<Tab>']]
  vim.cmd [[smap <expr> <Tab> vsnip#jumpable(1) ? '<Plug>(vsnip-jump-next)' : '<Tab>']]
  vim.cmd [[imap <expr> <S-Tab> vsnip#jumpable(-1) ? '<Plug>(vsnip-jump-prev)' : '<S-Tab>']]
  vim.cmd [[smap <expr> <S-Tab> vsnip#jumpable(-1) ? '<Plug>(vsnip-jump-prev)' : '<S-Tab>']]

  vim.cmd [[inoremap <silent><expr> <C-Space> compe#complete()]]
  vim.cmd [[inoremap <silent><expr> <CR> compe#confirm('<CR>')]]
  vim.cmd [[inoremap <silent><expr> <C-e> compe#close('<C-e>')]]
  vim.cmd [[inoremap <silent><expr> <C-f> compe#scroll({ 'delta': +4 })]]
  vim.cmd [[inoremap <silent><expr> <C-d> compe#scroll({ 'delta': -4 })]]
end

-- Finally, let's initialize the Elixir language server

-- Replace the following with the path to your installation
local path_to_elixirls = vim.fn.expand("~/dev/elixir-ls/rel/language_server.sh")

lspconfig.elixirls.setup({
  cmd = {path_to_elixirls},
  capabilities = capabilities,
  on_attach = on_attach,
  settings = {
    elixirLS = {
      -- I choose to disable dialyzer for personal reasons, but
      -- I would suggest you also disable it unless you are well
      -- aquainted with dialzyer and know how to use it.
      dialyzerEnabled = false,
      -- I also choose to turn off the auto dep fetching feature.
      -- It often get's into a weird state that requires deleting
      -- the .elixir_ls directory and restarting your editor.
      fetchDeps = false
    }
  }
})

EOF