In this article, I’m going to explain how to configure Neovim to work as an IDE for ESP32.
Before we start, we need to have ESP-IDF in our system. You can follow my Introduction to ESP32 development article for instructions on how to install it.
Lazy vim
I use lazy to manage my Neovim plugins, so let’s make sure it’s configured correctly. To do that, we need to add these lines to our init.lua (usually at ~/.config/nvim/init.lua):
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local lazypath = vim.fn.stdpath('data') .. '/lazy/lazy.nvim'
if not 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('plugins')
Plugins
We’ll be using a few plugins to configure Neovim. We will be putting our plugin files in ~/.config/nvim/lua/plugins/.
Nvim-LspConfig
This plugin is used to configure our LspClient. To configure it, we’ll create ~/.config/nvim/lua/plugins/nvim-lspconfig.lua with this content:
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return {
"neovim/nvim-lspconfig",
config = function()
require('lspconfig').clangd.setup {}
end
}
Mason
This plugin helps us to install different packages needed by other plugins. To configure it, we’ll create ~/.config/nvim/lua/plugins/mason.lua with this content:
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return {
'williamboman/mason.nvim',
build = ":MasonUpdate",
config = function()
require("mason").setup()
end
}
Mason-LspConfig
This plugin makes it easier to use Mason and Nvim-LspConfig together. It will make sure our LSP server is downloaded first (by mason) and then configured correctly (by nvim-lspconfig). To configure it, we’ll create ~/.config/nvim/lua/plugins/mason-lspconfig.lua with this content:
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return {
"williamboman/mason-lspconfig.nvim",
dependencies = {
'williamboman/mason.nvim',
},
config = function()
require("mason-lspconfig").setup({
ensure_installed = {
'clangd',
}
})
end
}
Nvim-Cmp
This plugin enables IDE-like auto-completion inside of Neovim. To configure it, we’ll create ~/.config/nvim/lua/plugins/nvim-cmp.lua with this content:
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return {
'hrsh7th/nvim-cmp',
dependencies = {
'hrsh7th/cmp-nvim-lsp'
},
config = function()
local cmp = require("cmp")
cmp.setup({
mapping = cmp.mapping.preset.insert({
['<C-b>'] = cmp.mapping.scroll_docs(-4),
['<C-f>'] = cmp.mapping.scroll_docs(4),
['<C-o>'] = cmp.mapping.complete(),
['<C-e>'] = cmp.mapping.abort(),
['<CR>'] = cmp.mapping.confirm({ select = true }),
}),
snippet = {
expand = function(args)
require('luasnip').lsp_expand(args.body)
end,
},
sources = cmp.config.sources({
{ name = 'nvim_lsp' },
{ name = 'luasnip' },
}, {
{ name = 'buffer' },
}),
})
end
}
Keyboard shortcuts
This step is optional, but it sets up some of my preferred keyboard shortcuts. Since these shortcuts are LSP specific, I put them inside ~/.config/nvim/lua/plugins/nvim-lspconfig.lua:
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vim.api.nvim_create_autocmd('LspAttach', {
desc = 'LSP actions',
callback = function(event)
-- Go to definition
vim.keymap.set('n', 'gd', '<cmd>lua vim.lsp.buf.definition()<cr>', {buffer = event.buf})
-- Return to previous location after going to definition
vim.api.nvim_set_keymap('n', 'gb', '<C-t>', {})
-- Go to definition in new tab
vim.api.nvim_set_keymap('n', 'gdt', '<C-w><C-]><C-w>T', {})
-- Code completion
vim.api.nvim_set_keymap('i', '<C-Space>', '<C-x><C-o>', {})
-- Don't open an empty buffer when triggering autocomplete
vim.o.completeopt = 'menu'
-- Show documentation for symbol
vim.keymap.set('n', 'K', '<cmd>lua vim.lsp.buf.hover()<cr>', {buffer = event.buf})
-- Format code
vim.keymap.set('n', 'F', '<cmd>lua vim.lsp.buf.format()<cr>', {buffer = event.buf})
-- Rename symbol
vim.keymap.set('n', '3r', '<cmd>lua vim.lsp.buf.rename()<cr>', {buffer = event.buf})
end
})
ESP-IDF Virtual Environment
ESP-IDF requires a virtual environment to work correctly. To ensure Neovim is running inside this environment, we need to use this command (replace /path-to-esp-idf with the path where you installed esp-idf):
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. /path-to-esp-idf/export.sh
compile_commands.json
The clangd Language Server requires a file named compile_commands.json. This file is generated by CMake automatically. We can generate it manually by running CMake for our project.
This is commonly done with these commands:
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mkdir build
cmake ..
Enjoy
The last step is to start Neovim from our project’s root and enjoy. The first time we start Neovim after making these changes, mason will need to download the clangd Language Server. This might take a couple of minutes, but won’t be necessary for future sessions.
Conclusion
Since ESP32 uses standard C/C++ tooling (CMake), configuring LSP was surprisingly easy. The only important gotcha is the need for the esp-idf virtual environment.
If you want an easy way to see it in action, I have added a ready to use example to my examples repo.
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