Autocompletion for Neovim

#neovim #vim #lua #programming

One of the coolest features that can make you more productive with NeoVim is autocompletion, so we have some plugins to choose between them based on the performance

YouCompleteMe
Coc.nvim

these plugins are great to use but they are very heavy because of Javascript and Python, so I decided to switch to another solution
and the solution is Lua Plugin called nvim-cmp
with this plugin you can add an auto-completion to your neovim with minimal performance, all you have to do is download the language server

Install

before installing the plugins you need to install Lua first

$ sudo pacman -S lua

and you need a Plugin manager you can choose between

vim-plug ( I use this )
Pathogen
Vundle

after installing the nvim-cmp plugin you have to install some external plugins

" ~/.config/nvim/init.nvim

    Plug 'hrsh7th/cmp-nvim-lsp'
    Plug 'hrsh7th/cmp-buffer'
    Plug 'hrsh7th/cmp-path'
    Plug 'hrsh7th/cmp-cmdline'
    Plug 'hrsh7th/nvim-cmp'
    Plug 'hrsh7th/vim-vsnip'

after installing the server of your language you may need some Lua code to enable it
so you can use this code to copy & paste into your init.nvim file
Also, Don't forget to check this page to get the right server for your language

in my case I'll install rust-analyzer

$ sudo pacman -S rust-analyzer

" ~/.config/nvim/init.nvim
lua <<EOF
  -- Setup nvim-cmp.
  local cmp = require'cmp'

  cmp.setup({
    snippet = {
      -- REQUIRED - you must specify a snippet engine
      expand = function(args)
        vim.fn["vsnip#anonymous"](args.body) -- For `vsnip` users.
        -- require('luasnip').lsp_expand(args.body) -- For `luasnip` users.
        -- require('snippy').expand_snippet(args.body) -- For `snippy` users.
        -- vim.fn["UltiSnips#Anon"](args.body) -- For `ultisnips` users.
      end,
    },
    mapping = {
      ['<C-b>'] = cmp.mapping(cmp.mapping.scroll_docs(-4), { 'i', 'c' }),
      ['<C-f>'] = cmp.mapping(cmp.mapping.scroll_docs(4), { 'i', 'c' }),
      ['<C-Space>'] = cmp.mapping(cmp.mapping.complete(), { 'i', 'c' }),
      ['<C-y>'] = cmp.config.disable, -- Specify `cmp.config.disable` if you want to remove the default `<C-y>` mapping.
      ['<C-e>'] = cmp.mapping({
        i = cmp.mapping.abort(),
        c = cmp.mapping.close(),
      }),
      ['<CR>'] = cmp.mapping.confirm({ select = true }), -- Accept currently selected item. Set `select` to `false` to only confirm explicitly selected items.
    },
    sources = cmp.config.sources({
      { name = 'nvim_lsp' },
      { name = 'vsnip' }, -- For vsnip users.
      -- { name = 'luasnip' }, -- For luasnip users.
      -- { name = 'ultisnips' }, -- For ultisnips users.
      -- { name = 'snippy' }, -- For snippy users.
    }, {
      { name = 'buffer' },
    })
  })

  -- Set configuration for specific filetype.
  cmp.setup.filetype('gitcommit', {
    sources = cmp.config.sources({
      { name = 'cmp_git' }, -- You can specify the `cmp_git` source if you were installed it.
    }, {
      { name = 'buffer' },
    })
  })

  -- Use buffer source for `/` (if you enabled `native_menu`, this won't work anymore).
  cmp.setup.cmdline('/', {
    sources = {
      { name = 'buffer' }
    }
  })

  -- Use cmdline & path source for ':' (if you enabled `native_menu`, this won't work anymore).
  cmp.setup.cmdline(':', {
    sources = cmp.config.sources({
      { name = 'path' }
    }, {
      { name = 'cmdline' }
    })
  })

  -- Setup lspconfig.
  local capabilities = require('cmp_nvim_lsp').update_capabilities(vim.lsp.protocol.make_client_capabilities())

  -- Replace <YOUR_LSP_SERVER> with each lsp server you've enabled.

  require'lspconfig'.rust_analyzer.setup{
      capabilities = capabilities,
  }

EOF