My neovim configuration written in Lua.

How to setup Neovim

Goal: Understand how neovim works so that you can customize and extend it natively in Lua.

Key components to understand:

1. How does neovim startup and what files does it source?
2. How do plugins work in neovim?
3. How does the LSP work in neovim?
4. What is a treesitter and how is it useful?

Help is your friend - use :h query<CTRL>-D to expand the query to a list of matching options.

Use this config out of the box

Downlaod neovim and build from source.

On Ubuntu 22.04, you can do -

git clone https://github.com/neovim/neovim
cd neovim
sudo apt install libtool-bin
sudo make
sudo make CMAKE_BUILD_TYPE=RelWithDebInfo
sudo make install

Install Packer:

git clone --depth 1 https://github.com/wbthomason/packer.nvim\
 ~/.local/share/nvim/site/pack/packer/start/packer.nvim

Clone this repo and move it to your config folder

git clone git@github.com:VastoLorde95/nvim-config.git
cp -R nvim-config/nvim ~/.config

Now, you must start neovim twice:

1. In the first startup, run :PackerSync to install all plugins.
2. In the second startup, treesitter will download whatever parsers it needs, after which you can run :Mason to install your favourite langauge severs. Make sure that each languge server is configured in after/plugin/lsp.lua

Config Directory Structure

See :h initialization to learn how nvim starts up. Run :lua print(vim.inspect(vim.api.nvim_list_runtime_paths())) to inspect your runtimepath

To learn more about how nvim finds files in the path, see:

:h runtimepath :h packpath :h package

While going through these docs, you will probably be curious to print stuff like stdpath('config') - this is available in :lua vim.fn.stdpath

Setup your nvim config directory in ~/.config/nvim/ like so

.
├── after/
├── init.lua
└── lua/
    ├── maps.lua
    ├── plugins.lua
    └── settings.lua

The following files will get sourced automatically:

• init.lua
• after/**/*.lua The files in the after directory will get sourced after all other files have been sourced.

The files in the lua directory are not sourced automatically, but are available to get required in your init.lua file, eg.

require('maps.lua')
require('plugins.lua')
require('settings.lua')

Install packer.nvim

Install plugin 'wbthomason/packer.nvim' to manage plugins.

To get started, first clone this repository to somewhere on your packpath, e.g.:

git clone --depth 1 https://github.com/wbthomason/packer.nvim\ ~/.local/share/nvim/site/pack/packer/start/packer.nvim

• How do plugins work in nvim? :h package

• How does require work in nvim/lua?

• Where does nvim look for files to source? :h runtimepath :h packpath

Using packer to change colorscheme.

To install a colorscheme:

Install 'sainnhe/sonokai' using packer.

Setup this colorscheme in after/plugin/color.lua

Configure statuline and tabline

For the statusline, we will use the plugin nvim-lualine/lualine.nvim

For the tabline, we will use neovim's v:lua feature to create the tabline string natively in Lua.

We will implement the tabline in lua/mytabline.lua and "require" it in our init.lua file. Will can register our function that creates the tabline string in the global environment using _G and then call it using %!v:lua.my_tabline().

We will also use the vim.fn construct to invoke vim functions and use their return values such as vim.fn.tabpagenr()

Setting up LSP

[//]: # TODO(apaliwal): Refactor nvim/after/plugins/lsp.lua, it has become too large.

Neovim comes with an inbuilt lsp client. See :h lsp

We will setup this client and its interaction with the LSP servers through the plugin: neovim/nvim-lspconfig

• What exactly is lspconfig even doing?

The plugin which provides some APIs to interact with the nvim core LSP client and also provides a collection of default configurations to interact with some popular LSP servers.

• Install neovim/nvim-lspconfig using packer.
• After installation, you can read the docs at :h lspconfig
• Install language servers eg. pylsp, sumneko_lua - Note that each language server must be installed externally.
• Configure each installed language server through lspconfig.SERVER_NAME.setup(), setting up their callbacks like on_attach, capabilities, etc. See :h lspconfig-setup to learn more about how to setup your LSP.
• See :h lspconfig-keybindings for suggested keybinds to use in the on_attach section in calls to setup().
• See :h lsp-buf for a list of capabilities in the LSP.

Intelligent Autocomplete with LSP

LSP provides manual autocompletion through omnifunc, but we must use a plugin for full autocomplete.

hrsh7th/nvim-cmp/ implements an autocomplete engine for neovim which can provide suggestions from external sources that have been registered in the neovim config.

In this config, we will use the following sources.

• hrsh7th/cmp-nvim-lsp
• hrsh7th/cmp-buffer
• hrsh7th/cmp-nvim-lua

In insert mode, cmp-nvim-lsp will have the highest priority for autocomplete, followed by cmp-nvim-lua and then cmp-buffer.

cmp-nvim-lua provides autocomplete support for the neovim Lua API.

cmp-buffer is configured so that all open buffers are used for autocomplete, except those with size > 10 MB.

[//]: # TODO(apaliwal): How is omnifunc different from the default ctrl-n ctrl-p in ins mode?

Setting up Treesitter

Treesitter provides incremental parsing of buffers to construct syntax trees. A "module" can "query" the treesitter syntax tree to implement features such as highlighting.

See :h nvim-treesitter-modules for a list of available modules.

To setup install the nvim-treesitter/nvim-treesitter plugin. All treesitter modules are disabled out of the box, and should be configured in the init.lua file via a call to

require("nvim-treesitter.configs").setup{}

Treesitter uses a different parser for every language, which needs to be generated via tree-sitter-cli from a grammar.js file, then compiled to a .so library that needs to be placed in neovim's runtimepath (typically under parser/{language}.so). To simplify this, nvim-treesitter provides commands to automate this process. If the language is already supported by nvim-treesitter, you can install it with

:TSInstall <language_to_install>

This command supports tab expansion.

You can also get a list of all available languages and their installation status with :TSInstallInfo.

To make sure a parser is at the latest compatible version (as specified in nvim-treesitter's lockfile.json), use :TSUpdate {language}. To update all parsers unconditionally, use :TSUpdate all or just :TSUpdate.

[//]: # TODO(apaliwal): How does it intregrate with LSP?
:h lsp-vs-treesitter

[//]: # TODO(apaliwal): How to integrate treesitter with the statusline?

Setting up Telescope

Telescope.nvim depends on plenary.nvim a library that contains utility functions for nvim writter purely in Lua.

The plugins can be found in the following repos:

nvim-lua/plenary.nvim nvim-telescope/telescope.nvim/

Telescope allows you to fuzzy find over arbirary lists in neovim and integrates seamlessly with LSP, Treesitter, Git and even Telescope itself.

All keymappings for telescope will begin with <Leader>f where 'f' stands for fuzzy.

Integration with git

We will use the plugin lewis6991/gitsigns.nvim to show diff status per line in the gutter next to the line numbers.

Langauge specific configurations

Python

Treesitter indentation does not work as expected for python. Apparently this is a bug in treesitter, so we turn off the indent module from treesitter.

Python uses two LSPs - pyright for static typechecking and autocomplete.

The configuration for another language server - pylsp is available. pylsp can be configured to use over half a dozen external tools for linting, code formatting, refactoring, etc. Currently, only pylint is available.

[//]: # TODO(apaliwal): Is it worth replacing pyright with mypy and jedi so that you
[//]: use only one LSP instead of two?

[//]: # TODO(apaliwal): Evaluate the performance implication of using two langauge
[//]: servers for python.

Lua

[//]: # TODO(apaliwal): Document the LSP setup for Lua and the neovim Lua api.

C++

[//]: # TODO(apaliwal): Setup langauge servers for C++

Continuous Integration

[//]: # TODO(apaliwal): How would you set up continuous integration for this config?

Use this for reference

Continuous integration for this repo should ensure the following

1. Neovim should start up without any errors or warnings
2. Startup time should be less than some reasonable value X.
3. Ensure that all keymaps work as expected.
4. Should ensure that there is no regression in the runtime of certain tasks.