Configure Nvim with Lua: auto completion, Cmp, treesitter and lsp (8)

8 min read, Published on Oct 11, 2022
Vim/Nvim
Lua

An important functionality in an IDE is the autocompletion and the highlight code, in Neovim we have plugins for this. Neovim supports LSP (Language Server Protocol). So, in this article we see how install and configure nvim-cmp, a completion engine plugin for neovim written in Lua. nvim-lspconfig, an LSP client, and nvim-treesitter, a plugin to provide some basic functionality such as highlighting.

  • We move to the nvim folder:
  cd .config/nvim

Install and configure nvim-cmp.nvim

  1. The first step: we add the plugin nvim-cmp to the plugins.lua file, with others plugins.
  nvim lua/configs/plugins.lua
  1. We add this and save it:
  -- ...others configs...
  return packer.startup(function(use)
    -- ...others plugins...

    use {
      'hrsh7th/nvim-cmp',
      requires = {
        "hrsh7th/cmp-buffer",
        "hrsh7th/cmp-nvim-lsp",
        "hrsh7th/cmp-path",
        "hrsh7th/cmp-nvim-lua",
        "onsails/lspkind-nvim",
        'hrsh7th/cmp-vsnip',
        'hrsh7th/vim-vsnip',
        'saadparwaiz1/cmp_luasnip',
        "L3MON4D3/LuaSnip",
        'rafamadriz/friendly-snippets'
      }
    }

    -- ...others configs...
  end)
  1. Install the packages:
  :PackerInstall
  1. Later, we create the cmp file.
  nvim lua/configs/cmp.lua
  1. We add this code and save it:
  local cmp_ok, cmp = pcall(require, "cmp")
  if not cmp_ok then
    return
  end

  local snip_ok, luasnip = pcall(require, "luasnip")
  if not snip_ok then
    return
  end

  -- Vscode-like: To use existing vs-code style snippets from a plugin (eg. rafamadriz/friendly-snippets) simply install the plugin and then add
  require("luasnip.loaders.from_vscode").lazy_load()

  --   פּ ﯟ   some other good icons
  local kind_icons = {
    Text = "",
    Method = "m",
    Function = "",
    Constructor = "",
    Field = "",
    Variable = "",
    Class = "",
    Interface = "",
    Module = "",
    Property = "",
    Unit = "",
    Value = "",
    Enum = "",
    Keyword = "",
    Snippet = "",
    Color = "",
    File = "",
    Reference = "",
    Folder = "",
    EnumMember = "",
    Constant = "",
    Struct = "",
    Event = "",
    Operator = "",
    TypeParameter = "",
  }

  cmp.setup({
      snippet = {
        -- REQUIRED - you must specify a snippet engine
        expand = function(args)
        --  vim.fn["vsnip#anonymous"](args.body) -- For `vsnip` users.
          luasnip.lsp_expand(args.body) -- For `luasnip` users.
        end
      },
      window = {
        completion = cmp.config.window.bordered(),
      },
      mapping = cmp.mapping.preset.insert({
        ['<C-b>'] = cmp.mapping.scroll_docs(-4),
        ['<C-f>'] = cmp.mapping.scroll_docs(4),
        ['<C-Space>'] = cmp.mapping.complete(),
        ['<C-e>'] = cmp.mapping.abort(),
        ['<CR>'] = cmp.mapping.confirm({ select = true }), -- Accept currently selected item. Set `select` to `false` to only confirm explicitly selected items.
      }),
      formatting = {
        fields = { "kind", "abbr", "menu" },
        format = function(entry, vim_item)
          -- Kind icons
          vim_item.kind = string.format("%s %s", kind_icons[vim_item.kind], vim_item.kind)
          vim_item.menu = ({
            nvim_lsp = "[LSP]",
            nvim_lua = "[NVIM_LUA]",
            luasnip = "[Snippet]",
            buffer = "[Buffer]",
            path = "[Path]",
          })[entry.source.name]
          return vim_item
        end,
      },
      sources = cmp.config.sources({
        { name = 'vsnip' }, -- For vsnip users.
        { name = 'luasnip' }, -- For luasnip users.
        { name = "buffer" },
        { name = "path" },
        { name = 'cmdline' },
        { name = 'nvim_lsp' },
        { name = 'nvim_lua' }
      }, {
        { name = 'buffer' },
      })
    })
  1. To use these settings, we need to call the cmp file in the main file (init.lua)
  nvim init.lua
  • Add this:
  require('configs.cmp')

Install and configure nvim-lspconfig

  1. The first step: we add the plugin nvim-lspconfig to the plugins.lua file.
  nvim lua/configs/plugins.lua
  1. We add this and save it:
  -- ...others configs...
  return packer.startup(function(use)
    -- ...others plugins...

    -- LSP
   use {
      "williamboman/mason.nvim",
      "williamboman/mason-lspconfig.nvim",
      "neovim/nvim-lspconfig",
   }

    -- ...others configs...
  end)
  • Here, we are use mason-lspconfig.nvim a Neovim plugin that allows you to easily manage external editor tooling such as LSP servers.
  1. Install the packages:
  :PackerInstall

  • In my case only install lua, svelte, typescript, tailwindcss and css LSP, but you are free to install others from lsp server configurations

  • For Lua:

  :LspInstall sumneko_lua
  • For typescript:
  npm install -g typescript typescript-language-server
  • In Neovim:
  :LspInstall tsserver
  • For svelte:
  npm install -g svelte-language-server
  • In Neovim:
  :LspInstall svelte
  • For css:
  npm i -g vscode-langservers-extracted
  • In Neovim:
  :LspInstall cssls
  • For tailwindcss:
  npm install -g @tailwindcss/language-server
  • In Neovim:
  :LspInstall tailwindcss
  1. Later, we create the lsp file.
  nvim lua/configs/lsp.lua
  1. We add this code and save it:
  local ok, mason = pcall(require, 'mason')
  if not ok then
    return
  end

  local ok_mason_lsp, mason_lspconfig = pcall(require, 'mason-lspconfig')
  if not ok_mason_lsp then
    return
  end

  local ok_lsp, lspconfig = pcall(require, 'lspconfig')
  if not ok_lsp then
    return
  end

  -- Mappings.
  -- See `:help vim.diagnostic.*` for documentation on any of the below functions
  local opts = { noremap=true, silent=true }
  vim.keymap.set('n', '<space>e', vim.diagnostic.open_float, opts)
  vim.keymap.set('n', '[d', vim.diagnostic.goto_prev, opts)
  vim.keymap.set('n', ']d', vim.diagnostic.goto_next, opts)
  vim.keymap.set('n', '<space>q', vim.diagnostic.setloclist, opts)

  -- Use an on_attach function to only map the following keys
  -- after the language server attaches to the current buffer
  local on_attach = function(client, bufnr)
    -- Enable completion triggered by <c-x><c-o>
    vim.api.nvim_buf_set_option(bufnr, 'omnifunc', 'v:lua.vim.lsp.omnifunc')

    -- Mappings.
    -- See `:help vim.lsp.*` for documentation on any of the below functions
    local bufopts = { noremap=true, silent=true, buffer=bufnr }
    vim.keymap.set('n', 'gD', vim.lsp.buf.declaration, bufopts)
    vim.keymap.set('n', 'gd', vim.lsp.buf.definition, bufopts)
    vim.keymap.set('n', 'K', vim.lsp.buf.hover, bufopts)
    vim.keymap.set('n', 'gi', vim.lsp.buf.implementation, bufopts)
    vim.keymap.set('n', '<C-k>', vim.lsp.buf.signature_help, bufopts)
    vim.keymap.set('n', '<space>wa', vim.lsp.buf.add_workspace_folder, bufopts)
    vim.keymap.set('n', '<space>wr', vim.lsp.buf.remove_workspace_folder, bufopts)
    vim.keymap.set('n', '<space>wl', function()
      print(vim.inspect(vim.lsp.buf.list_workspace_folders()))
    end, bufopts)
    vim.keymap.set('n', '<space>D', vim.lsp.buf.type_definition, bufopts)
    vim.keymap.set('n', '<space>rn', vim.lsp.buf.rename, bufopts)
    vim.keymap.set('n', '<space>ca', vim.lsp.buf.code_action, bufopts)
    vim.keymap.set('n', 'gr', vim.lsp.buf.references, bufopts)
    vim.keymap.set('n', '<space>f', function() vim.lsp.buf.format { async = true } end, bufopts)
  end

  local lsp_flags = {
    -- This is the default in Nvim 0.7+
    debounce_text_changes = 150,
  }


  mason.setup()
  mason_lspconfig.setup({
      ensure_installed = { "sumneko_lua" }
  })
  -- config for Lua
  lspconfig.sumneko_lua.setup {
    on_attach = on_attach,
    flags = lsp_flags,
    settings = {
      Lua = {
        runtime = {
          -- Tell the language server which version of Lua you're using (most likely LuaJIT in the case of Neovim)
          version = 'LuaJIT',
        },
        diagnostics = {
          -- Get the language server to recognize the `vim` global
          globals = {'vim'},
        },
        workspace = {
          -- Make the server aware of Neovim runtime files
          library = vim.api.nvim_get_runtime_file("", true),
        },
        -- Do not send telemetry data containing a randomized but unique identifier
        telemetry = {
          enable = false,
        },
      },
    },
  }

  -- config for typescript
  lspconfig.tsserver.setup{
    on_attach = on_attach,
    flags = lsp_flags,
  }
  -- config for svelte
  lspconfig.svelte.setup{
    on_attach = on_attach,
    flags = lsp_flags,
  }
  1. To use these settings, we need to call the cmp file in the main file (init.lua)
  nvim init.lua
  • Add this:
  require('configs.lsp')

Note: With gd you go to method definition.

Install and configure nvim-treesitter

  1. The first step: we add the plugin nvim-treesitter to the plugins.lua file.
  nvim lua/configs/plugins.lua
  1. We add this and save it:
  -- ...others configs...
  return packer.startup(function(use)
    -- ...others plugins...

    -- Treesitter
   use {
      'nvim-treesitter/nvim-treesitter',
      run = function() require('nvim-treesitter.install').update({ with_sync = true }) end,
    }
   use "p00f/nvim-ts-rainbow"
   use "nvim-treesitter/playground"

    -- ...others configs...
  end)
  1. Install the packages:
  :PackerInstall

  • In my case only install lua, svelte, typescript and css highlighting, but you are free to install others from supported languages

  • For Lua:

  :TSInstall lua
  • For typescript:
  :TSInstall typescript
  • For svelte:
  :TSInstall svelte
  • For css:
  :TSInstall css
  1. Later, we create the treesitter file.
  nvim lua/configs/treesitter.lua
  1. We add this code and save it:
  local ok, configs = pcall(require, 'nvim-treesitter.configs')

  if not ok then
    return
  end

  configs.setup({
    ensure_installed = {
      'lua',
      'typescript',
      'svelte',
      'css'
    },
    highlight = {
      enable = true,
      -- Setting this to true will run `:h syntax` and tree-sitter at the same time.
      -- Set this to `true` if you depend on 'syntax' being enabled (like for indentation).
      -- Using this option may slow down your editor, and you may see some duplicate highlights.
      -- Instead of true it can also be a list of languages
      additional_vim_regex_highlighting = false,
    },
    rainbow = {
      enable = true,
      -- disable = { "jsx", "cpp" }, list of languages you want to disable the plugin for
      extended_mode = true, -- Also highlight non-bracket delimiters like html tags, boolean or table: lang -> boolean
      max_file_lines = nil, -- Do not enable for files with more than n lines, int
      -- colors = {}, -- table of hex strings
      -- termcolors = {} -- table of colour name strings
    },
    playground = {
      enable = true,
      disable = {},
      updatetime = 25, -- Debounced time for highlighting nodes in the playground from source code
      persist_queries = false, -- Whether the query persists across vim sessions
      keybindings = {
        toggle_query_editor = 'o',
        toggle_hl_groups = 'i',
        toggle_injected_languages = 't',
        toggle_anonymous_nodes = 'a',
        toggle_language_display = 'I',
        focus_language = 'f',
        unfocus_language = 'F',
        update = 'R',
        goto_node = '<cr>',
        show_help = '?',
      },
    }
  })
  1. To use these settings, we need to call the cmp file in the main file (init.lua)
  nvim init.lua
  • Add this:
  require('configs.treesitter')

And that’s it!! You can use Cmp, Lsp Config and Treesitter for autocompletion and highlighting the code.

Directory

We have the directory of folders like this:

nvim
├─ init.lua
└─ lua
  └─ configs
    └─ options
    |   └─ init.lua
    └─ keymaps.lua
    └─ plugins.lua
    └─ impatient.lua
    └─ colorscheme.lua
    └─ nvim-tree.lua
    └─ lualine.lua
    └─ bufferline.lua
    └─ telescope.lua
    └─ cmp.lua
    └─ lsp.lua
    └─ treesitter.lua

Conclusion

In this article we learned how to install and configure nvim-cmp, a completion engine plugin for neovim written in Lua. nvim-lspconfig, an LSP client, and nvim-treesitter, a plugin to provide some basic functionality such as highlighting.. I hope it will be helpful for those who want to experiment.

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