使用 nvim-cmp 和 lsp 的最小 NeoVim lua 配置

Question

I'm trying to write my own NeoVim Lua based config, stripped down to the minimum I need and with the goal to understand at least most of the config. LSP setup is working fine and is the only source I configured for nvim-cmp:

local cmp = require("cmp")                                                                                                                                                              
 
cmp.setup {                                                                                                                                                                             
  sources = {                                                                                                                                                                           
    { name = 'nvim_lsp' }                                                                                                                                                               
   }                                                                                                                                                                                     
}                                                                                                                                                                                       
local capabilities = vim.lsp.protocol.make_client_capabilities()                                                                                                                        
capabilities = require('cmp_nvim_lsp').update_capabilities(capabilities) 

After some startup delay the completion is working in the sense that I see popups with proposed completions, based on information from LSP.

But I cannot select any of the proposed completions. I can just continue to type which reduces the proposed completions, but I cannot use tab, arrow keys, ... to select an entry from the popup. I saw in the docs that one can define keyboard mappings but cannot make sense out of them. They are all rather sophisticated, require a snippet package to be installed, ...

I would prefer to select the next completion via tab and to navigate them via arrow key. "Enter" should select the current one.

Could somebody show me a minimal configuration for this setup or point me to more "basic" docs?

Answer 1

Nvim-cmp requires you to set the mapping for tab and other keys explicitly, here is my working example :

local cmp = require'cmp'
local lspkind = require'lspkind'

cmp.setup({
  snippet = {
    expand = function(args)
      -- For `ultisnips` user.
      vim.fn["UltiSnips#Anon"](args.body)
    end,
  },
  mapping = cmp.mapping.preset.insert({
          ['<Tab>'] = function(fallback)
            if cmp.visible() then
              cmp.select_next_item()
            else
              fallback()
            end
          end,
          ['<S-Tab>'] = function(fallback)
            if cmp.visible() then
              cmp.select_prev_item()
            else
              fallback()
            end
          end,
          ['<CR>'] = cmp.mapping.confirm({ select = true }),
          ['<C-e>'] = cmp.mapping.abort(),
          ['<Esc>'] = cmp.mapping.close(),
          ['<C-d>'] = cmp.mapping.scroll_docs(-4),
          ['<C-f>'] = cmp.mapping.scroll_docs(4),
        }),
  sources = {
    { name = 'nvim_lsp' }, -- For nvim-lsp
    { name = 'ultisnips' }, -- For ultisnips user.
    { name = 'nvim_lua' }, -- for nvim lua function
    { name = 'path' }, -- for path completion
    { name = 'buffer', keyword_length = 4 }, -- for buffer word completion
    { name = 'omni' },
    { name = 'emoji', insert = true, } -- emoji completion
  },
  completion = {
    keyword_length = 1,
    completeopt = "menu,noselect"
  },
  view = {
    entries = 'custom',
  },
  formatting = {
    format = lspkind.cmp_format({
      mode = "symbol_text",
      menu = ({
        nvim_lsp = "[LSP]",
        ultisnips = "[US]",
        nvim_lua = "[Lua]",
        path = "[Path]",
        buffer = "[Buffer]",
        emoji = "[Emoji]",
          omni = "[Omni]",
      }),
    }),
  },
})

This is working great for me. The mapping part corresponds to the config for key mapping in the table. You can tweak your conf based on my config to make it work for you.