Transform Your Neovim into a IDE: A Step-by-Step Guide

Version info

I use a Macbook pro-2020 Intel Edition with macOS 13.2. This is my Nvim edition:

NVIM v0.9.5
Build type: Release
LuaJIT 2.1.1710088188

   system vimrc file: "$VIM/sysinit.vim"
  fall-back for $VIM: "/usr/local/Cellar/neovim/0.9.5/share/nvim"

Run :checkhealth for more info

Why Neovim

After using Vim for one year, I find myself having trouble in configure ~/.vimrc. The syntax of Vimscript is not my liking, leading me to switch Neovim(Nvim). Rather than migrating my old ~/.vimrc. I decided to start from scratch and take this opportunity to re-evaluate my previous Vim configuration. I aim to replace my plugins with the latest SOTA(State-of-the-art) alternatives. It’s been some time since I last edited my ~/.vimrc

In my opinion, it’s essential to understand the meaning behind each option and statement in the configuration file. That’s the approach I took in this post. My goal is to make the configuration files self-contained and easily understandable. To achieve this, I aim to provide clear explanations for each setting and include comments to enhance readability.

💡 Please note that I may have missed some options. However, as a reminder, you can always access the help docs in the Nvim by typing :h <name> to get more information

💡 This post assumes that you have a basic understanding of Vim

The basics

Lua

In my Nvim configuration, I will use the Lua programming language as much as possible. Thus, it’s recommended that the reader familiarize themselves with Lua. Take a look at Learn Lua in Y minutes

Configurations files paths

The configuration directory for Nvim is located at ~/.config/nvim. On Linux/Mac, Nvim will read ~/.config/nvim/init.lua when it starts up. Theoretically, we can put everything inside this single file. It’s a bad practice though. To keep things organized, I prefer to break it down into smaller, more manageable parts.

If you follow this post to configure your Nvim, your ~/.config/nvim should look like this⬇️

nvim
├── init.lua
└── lua
    ├── colorscheme.lua
    ├── config
    │   └── nvim-cmp.lua
    ├── keymaps.lua
    ├── lsp.lua
    ├── options.lua
    └── plugins.lua

The explanations

• init.lua is the entry point. We will “import” other *.lua files in init.lua
  • colorscheme.lua for the theme
  • keymaps.lua for key mappings
  • lsp.lua for the LSP support
  • options.lua for some global options
  • plugins.lua for third-party plugins
• Put the configurations of third-party plugins in this config folder. For example, nvim-cmp.lua for the nvim-cmp plugin
• lua folder. When we call require to import a module in Lua, it will search this folder.
  • Replace the path separator / with ., and remove the suffix - .lua. That’s how you get the parameter of require
  • For example, to import nvim-cmp.lua, you should write require('config.nvim-cmp')

Options

We mainly use these: vim.g, vim.opt, and vim.cmd. I made a cheatsheet below:

key mappings

The syntax of key binding in Nvim:

vim.keymap.set(<mode>, <key>, <action>, <opts>)

For a detailed explanation, please refer to :h vim.keymap.set

Configure Nvim from scratch

Now we can configure Nvim step by step :)

Install Neovim

I am a Mac user, so I use Homebrew to install Nvim¹

$ brew install neovim 

After completing the installation, If the ~/.config/nvim/ directory doesn’t exist, you should create the folder and init.lua file

$ mkdir ~/.config/nvim
$ mkdir ~/.config/nvim/lua
$ touch ~/.config/nvim/init.lua

💡 Please note that after making any modifications to the *.lua files, you need to restart the Nvim to see the changes take effect. I will assume that you restart your Nvim after each section

Options configuration

The features:

• Use the system’s clipboard
• Use the mouse in Nvim
• Tab and whitespace
• UI configuration
• Smart search

Create ~/.config/nvim/lua/options.lua file and edit:

-- Hint: use `:h <option>` to figure out the meaning if needed
vim.opt.clipboard = 'unnamedplus'   -- use system clipboard 
vim.opt.completeopt = {'menu', 'menuone', 'noselect'}
vim.opt.mouse = 'a'                 -- allow the mouse to be used in Nvim

-- Tab
vim.opt.tabstop = 4                 -- number of visual spaces per TAB
vim.opt.softtabstop = 4             -- number of spacesin tab when editing
vim.opt.shiftwidth = 4              -- insert 4 spaces on a tab
vim.opt.expandtab = true            -- tabs are spaces, mainly because of python

-- UI config
vim.opt.number = true               -- show absolute number
vim.opt.relativenumber = true       -- add numbers to each line on the left side
vim.opt.cursorline = true           -- highlight cursor line underneath the cursor horizontally
vim.opt.splitbelow = true           -- open new vertical split bottom
vim.opt.splitright = true           -- open new horizontal splits right
-- vim.opt.termguicolors = true        -- enabl 24-bit RGB color in the TUI
vim.opt.showmode = false            -- we are experienced, wo don't need the "-- INSERT --" mode hint

-- Searching
vim.opt.incsearch = true            -- search as characters are entered
vim.opt.hlsearch = false            -- do not highlight matches
vim.opt.ignorecase = true           -- ignore case in searches by default
vim.opt.smartcase = true            -- but make it case sensitive if an uppercase is entered

Then edit the init.lua file, use require to import options.lua file

require('options')        

Key mappings configuration

The features:

• Use <C-h/j/k/l> to move the cursor among windows
• Use Ctrl + arrow keys to resize windows
• In select mode, we can use Tab or Shift-Tab to change the indentation repeatedly

Create ~/.config/nvim/lua/keymaps.lua and edit:

-- define common options
local opts = {
    noremap = true,      -- non-recursive
    silent = true,       -- do not show message
}

-----------------
-- Normal mode --
-----------------

-- Hint: see `:h vim.map.set()`
-- Better window navigation
vim.keymap.set('n', '<C-h>', '<C-w>h', opts)
vim.keymap.set('n', '<C-j>', '<C-w>j', opts)
vim.keymap.set('n', '<C-k>', '<C-w>k', opts)
vim.keymap.set('n', '<C-l>', '<C-w>l', opts)

-- Resize with arrows
-- delta: 2 lines
vim.keymap.set('n', '<C-Up>', ':resize -2<CR>', opts)
vim.keymap.set('n', '<C-Down>', ':resize +2<CR>', opts)
vim.keymap.set('n', '<C-Left>', ':vertical resize -2<CR>', opts)
vim.keymap.set('n', '<C-Right>', ':vertical resize +2<CR>', opts)

-----------------
-- Visual mode --
-----------------

-- Hint: start visual mode with the same area as the previous area and the same mode
vim.keymap.set('v', '<', '<gv', opts)
vim.keymap.set('v', '>', '>gv', opts)

Edit init.lua and import keymaps.lua

...  -- rest of the configuration
require('keymaps')        

Install package manager

A powerful Nvim should be augmented with third-party plugins. I have selected lazy.nvim as my plugin manager, which has several amazing features including:

• 🧪 Correct sequencing of dependencies
• 🔒 Lockfile lazy-lock.json to keep track of installed plugins
• …

Create ~/.config/nvim/lua/plugins.lua and paste the following code. At the moment, I haven’t added any third-party packages. The template code will bootstrap lazy.nvim for us.

local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
if not (vim.uv or vim.loop).fs_stat(lazypath) then
  vim.fn.system({
    "git",
    "clone",
    "--filter=blob:none",
    "https://github.com/folke/lazy.nvim.git",
    "--branch=stable", -- latest stable release
    lazypath,
  })
end
vim.opt.rtp:prepend(lazypath)

require("lazy").setup({})

💡 The syntax of adding a third-party plugin in lazy.nvim is adding specification in the ... of require("lazy").setup({}).

Again, import plugins.lua in init.lua

...  -- rest of the configuration
require('plugins')        

If you see a black window with no content when opening Nvim, just wait for a moment as lazy.nvim is in the process of installing itself☕️. After the Dashboard appears, you may type :Lazy to check if it works correctly.

Colorscheme

My favorite theme - monokai.nvim. Add this plugin in plugins.lua

...  -- rest of the configuration
require("lazy").setup({
    "tanvirtin/monokai.nvim",
})

Save the changes and wait for lazy.nvim to finish installing. Create ~/.config/nvim/lua/colorscheme.lua and edit:

-- define your colorscheme here
local colorscheme = 'monokai_pro'

local is_ok, _ = pcall(vim.cmd, "colorscheme " .. colorscheme)
if not is_ok then
    vim.notify('colorscheme ' .. colorscheme .. ' not found!')
    return
end

The pcall here refers to a protected call in Lua, which will return a boolean value to indicate its successful execution(a similar approach can be found in Go with the use of err). By using pcall instead of vim.cmd('colorscheme monokai_pro'), we can avoid some annoying error messages in case the colorscheme is not installed²

Again, import colorscheme.lua in init.lua

...  -- rest of the configuration
require('colorscheme')

Auto-completion

It can be quite complicated to configure auto-completion manually, which is why we use some fantastic plugins to ease the burden. Now I will discuss a simpler solution I have found.

First, use this plugin nvim-cmp, which can manage many completion sources for us. It can also let us customize the completion menu etc.

Create ~/.config/nvim/lua/config/nvim-cmp.lua and edit

local has_words_before = function()
    unpack = unpack or table.unpack
    local line, col = unpack(vim.api.nvim_win_get_cursor(0))
    return col ~= 0 and vim.api.nvim_buf_get_lines(0, line - 1, line, true)[1]:sub(col, col):match("%s") == nil
end

local luasnip = require("luasnip")
local cmp = require("cmp")

cmp.setup({
    snippet = {
        -- REQUIRED - you must specify a snippet engine
        expand = function(args)
            require('luasnip').lsp_expand(args.body) -- For `luasnip` users.
        end,
    },
    mapping = cmp.mapping.preset.insert({
        -- Use <C-b/f> to scroll the docs
        ['<C-b>'] = cmp.mapping.scroll_docs( -4),
        ['<C-f>'] = cmp.mapping.scroll_docs(4),
        -- Use <C-k/j> to switch in items
        ['<C-k>'] = cmp.mapping.select_prev_item(),
        ['<C-j>'] = cmp.mapping.select_next_item(),
        -- Use <CR>(Enter) to confirm selection
        -- Accept currently selected item. Set `select` to `false` to only confirm explicitly selected items.
        ['<CR>'] = cmp.mapping.confirm({ select = true }),

        -- A super tab
        -- sourc: https://github.com/hrsh7th/nvim-cmp/wiki/Example-mappings#luasnip
        ["<Tab>"] = cmp.mapping(function(fallback)
            -- Hint: if the completion menu is visible select next one
            if cmp.visible() then
                cmp.select_next_item()
            elseif has_words_before() then
                cmp.complete()
            else
                fallback()
            end
        end, { "i", "s" }), -- i - insert mode; s - select mode
        ["<S-Tab>"] = cmp.mapping(function(fallback)
            if cmp.visible() then
                cmp.select_prev_item()
            elseif luasnip.jumpable( -1) then
                luasnip.jump( -1)
            else
                fallback()
            end
        end, { "i", "s" }),
    }),

  -- Let's configure the item's appearance
  -- source: https://github.com/hrsh7th/nvim-cmp/wiki/Menu-Appearance
  formatting = {
      -- Set order from left to right
      -- kind: single letter indicating the type of completion
      -- abbr: abbreviation of "word"; when not empty it is used in the menu instead of "word"
      -- menu: extra text for the popup menu, displayed after "word" or "abbr"
      fields = { 'abbr', 'menu' },

      -- customize the appearance of the completion menu
      format = function(entry, vim_item)
          vim_item.menu = ({
              nvim_lsp = '[Lsp]',
              luasnip = '[Luasnip]',
              buffer = '[File]',
              path = '[Path]',
          })[entry.source.name]
          return vim_item
      end,
  },

  -- Set source precedence
  sources = cmp.config.sources({
      { name = 'nvim_lsp' },    -- For nvim-lsp
      { name = 'luasnip' },     -- For luasnip user
      { name = 'buffer' },      -- For buffer word completion
      { name = 'path' },        -- For path completion
  })
})

Then we modify plugins.lua file to add the plugins needed:

...  -- rest of the configuration
require("lazy").setup({
	-- Vscode-like pictograms
	{
		"onsails/lspkind.nvim",
		event = { "VimEnter" },
	},
	-- Auto-completion engine
	{
		"hrsh7th/nvim-cmp",
		dependencies = {
			"lspkind.nvim",
			"hrsh7th/cmp-nvim-lsp", -- lsp auto-completion
			"hrsh7th/cmp-buffer", -- buffer auto-completion
			"hrsh7th/cmp-path", -- path auto-completion
			"hrsh7th/cmp-cmdline", -- cmdline auto-completion
		},
		config = function()
			require("config.nvim-cmp")
		end,
	},
	-- Code snippet engine
	{
		"L3MON4D3/LuaSnip",
		version = "v2.*",
	},
    ...  -- rest of the configuration
})

Explanations:

• cmp.setup function accepts a Lua table, which defines some options for customization. You will find that plenty of plugins follow this API design. It’s a common practice.
• LuaSnip is a code snippet engine. The nvim-cmp says that we should pick a code snippet engine at least. Just ignore this if you don’t need this
• We can use config = function() ... end in lazy.nvim to specify the code to run after the plugin is loaded. I set it to load the nvim-cmp.lua file
• The nvim-cmp is the main plugin we care about. All other plugins begin with cmp- is the completion sources helper used by nvim-cmp. The lspkind.nvim will make it more beautiful :)

Key mappings in nvim-cmp

Use mapping = .... The syntax is ['<key-binding>'] = cmp.mapping.xxx,. Different cmp.mapping.xxx options can be found in the manual. If you want to set a different key-binding, just change the [...]

My key mappings:

1. Use <C-k/j> or “/” to move among completion items
2. Use <C-b/f> to scroll among the doc of completion item
3. Use <CR> to confirm completion

Completion menu in nvim-cmp

Use formatting = ...:

• Use fields to specify the appearance of each completion item
• Use format = function(...) to set the text for each completion source. You can specify completion sources in sources = ...

🎙️ You can use basic completion now ~

LSP

To turn Nvim into an IDE, it is necessary to rely on LSP³. It is cumbersome to install and configure LSP one by one manually, as different LSPs have different installation steps, and it is inconvenient for future management. That’s where tools like mason.nvim and mason-lspconfig.nvim come in to make our lives easier 🤗

Modify the plugins.lua file:

...  -- rest of the configuration
require("lazy").setup({
	-- LSP manager
	"williamboman/mason.nvim",
	"williamboman/mason-lspconfig.nvim",
	"neovim/nvim-lspconfig",
    ...  -- rest of the configuration
})

Create a ~/.config/nvim/lua/lsp.lua file to manage it. Let’s configure mason and mason-lspconfig first

require('mason').setup({
    ui = {
        icons = {
            package_installed = "✓",
            package_pending = "➜",
            package_uninstalled = "✗"
        }
    }
})

require('mason-lspconfig').setup({
    -- A list of servers to automatically install if they're not already installed
    ensure_installed = { 'pylsp', 'lua_ls', 'rust_analyzer' },
})

💡 Add whatever LSP you like in the ensure_installed, the complete list can be found in server_configurations. I use the two programming languages python/rust, and because we use Lua to configure Nvim, we also added lua_ls here

After configuring the mason-lspconfig, we can now configure nvim-lspconfig now. Because the configuration code is relatively long, I only show the configurations for pylsp. The latest file can be found here.

💡 Each LSP may have its options to configure, check the corresponding GitHub repo to get more info, or you can just set on_attach = on_attach.

Add the following code to the nvim/lua/lsp.lua file

...  -- rest of the configuration
-- Set different settings for different languages' LSP
-- LSP list: https://github.com/neovim/nvim-lspconfig/blob/master/doc/server_configurations.md
-- How to use setup({}): https://github.com/neovim/nvim-lspconfig/wiki/Understanding-setup-%7B%7D
--     - the settings table is sent to the LSP
--     - on_attach: a lua callback function to run after LSP attaches to a given buffer
local lspconfig = require('lspconfig')

-- Customized on_attach function
-- 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')

    -- 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

-- Configure each language
-- How to add LSP for a specific language?
-- 1. use `:Mason` to install corresponding LSP
-- 2. add configuration below
lspconfig.pylsp.setup({
	on_attach = on_attach,
})

The key-binding here is quite similar to what we did in nvim-cmp. Refer to the manual as you wish.

Append a line in init.lua

...  -- rest of the configuration
require('lsp')

Once you’ve restarted Nvim, take a look at the status bar below. You should notice Mason is busy installing the specified LSPs (Keep in mind that Nvim should not be closed during this process). To track the installation progress, enter :Mason in Nvim. While you wait, you can type g? to get additional information about the Mason plugin.

Now we have a lightweight IDE🎉🎉🎉

Wrap-up

With this configuration, we successfully turned Nvim into a lightweight IDE, which supports code highlighting, code completion, syntax checking, and other functionalities. It is completely open source and free 🤗.

I realized that even after trying different code editors and IDEs, I always found myself searching for Vim support. So I chose to turn Nvim into an IDE and host the configuration files on my martinlwx/dotfiles. In this way, I can easily clone my configuration files to any new machine and have a consistent programming experience across machines.

Polishing tools requires effort and time. To understand the purpose of each option, I had to search for various materials. However, despite the challenges, I firmly believe that it’s worth it. Understanding your tools allows you to further extend and customize them. This article aims to present a simple and straightforward configuration, but there are still many beautification and customization things that can be done, including many excellent third-party plug-ins that have not been mentioned yet. The exploration and discovery are left to the readers

Refs