- \n
- Nvim lsp: configure language servers, shortcuts for listing your symbols, rename, code actions, get definition\/declaration, workspace, highlights (this article)<\/li>\n\n\n\n
- Nvim lsp: diagnostics – keybindings, error\/warning signs, floating and virtual texts<\/a><\/li>\n\n\n\n
- Nvim lsp: autocompletion – mapping, snippets, fuzzy search, and icons<\/a><\/li>\n<\/ol>\n\n\n\n
I recommend you to follow all three articles in the above order.<\/p>\n\n\n\n
Table of Contents<\/h2>\n\n\n\n
- \n
- What are Language Server and LSP<\/a><\/li>\n\n\n\n
- Install useful plug-ins for nvim lsp<\/a><\/li>\n\n\n\n
- Install necessary language servers<\/a><\/li>\n\n\n\n
- Set up key bindings in neovim-lsp<\/a>\n
- \n
- Definition and Declaration in neovim lsp<\/a><\/li>\n\n\n\n
- Hover information in neovim lsp<\/a><\/li>\n\n\n\n
- Implementation in nvim lsp<\/a><\/li>\n\n\n\n
- Signature help in neovim lsp<\/a><\/li>\n\n\n\n
- Workspace in neovim lsp<\/a><\/li>\n\n\n\n
- Rename symbols in neovim lsp<\/a><\/li>\n\n\n\n
- Code actions in nvim lsp<\/a><\/li>\n\n\n\n
- List all references to the symbol using neovim lsp<\/a><\/li>\n\n\n\n
- Formatting in nvim lsp<\/a><\/li>\n\n\n\n
- Get information about language servers attached to neovim<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n
- Highlight symbol under the cursor using nvim lsp<\/a><\/li>\n\n\n\n
- Language Server Configurations<\/a>\n
- \n
- Configure several language servers at once in nvim<\/a><\/li>\n\n\n\n
- Configure each server separately in nvim-lsp<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n
- Way Ahead<\/a><\/li>\n<\/ul>\n\n\n\n
What are Language Server and LSP<\/h2>\n\n\n\n
Language Servers<\/strong>, like any other servers, run in the background of your computer and they serve their services such as autocompletion, diagnostics (linting), formatting, hover information, renaming, etc. to any ‘client<\/strong>‘ such as neovim<\/strong>\/vscode\/atom\/sublime. These services are served by following a special communication protocol called Language Server Protocol<\/a>.<\/p>\n\n\n\n
LSP is a rather new protocol and most modern editors are starting to support this. As of 10 June 2022, Vim still does not support this natively. You need to install special plugins in vim for this feature. But neovim, starting from version 0.5<\/strong>, has started to support this in its core version itself (use the command
nvim --version<\/code> to find your version of neovim). You don’t have to install any plugin in neovim for this. At the same time, there are some related plug-ins in neovim which makes configuring and using language servers easy. I will be recommending such plug-ins in the upcoming paras.<\/p>\n\n\n\nFor each famous programming language, we have at least one language server. For example,
bash-language-server<\/code> (sometimes also calledbashls<\/code>) is forbash<\/code> language,pyright<\/code> is forpython<\/code> language,lua-language-server<\/code> (also known assumneko_lua<\/code>) forlua<\/code> language.<\/p>\n\n\n\nBefore language servers came into existence, each editor needed to provide dedicated support for each language in its own unique way. It was a cumbersome process. But now, language developers only need to develop the language and the corresponding server. And editors supporting LSP can connect with these servers without having any dedicated support for the language itself.<\/p>\n\n\n\n
Install useful plug-ins for nvim lsp<\/h2>\n\n\n\n
Use your favorite plug-in managers to install these plug-ins:<\/p>\n\n\n\n
- \n
- collection of configurations for builtin neovim-lsp:
neovim\/nvim-lspconfig<\/code><\/li>\n\n\n\n- Plug-in
hrsh7th\/nvim-cmp<\/code> provides additional completion capabilities.<\/li>\n<\/ul>\n\n\n\nInstall necessary language servers<\/h2>\n\n\n\n
In this article, I will explain everything using the
lua-language-server<\/code>,pyright<\/code> (python-language-server<\/code>) andbash-language-server<\/code>. For others, the procedure is exactly similar. To get a list of available servers, visit the neovim site for server configuration<\/a>.<\/p>\n\n\n\nThere are many ways to install the servers:<\/p>\n\n\n\n
- \n
- Using your distributions’ official package managers <\/strong>(ex –
apt<\/code> for Debian,pacman<\/code> for Arch Linux). This is best<\/strong> of all because now, the packages will be upgraded by your package managers and you don’t have to do that manually.<\/li>\n\n\n\n- However, If you cannot install it using the above method, just search on Google, head over to the official sites <\/strong>of these servers, and follow the recommended methods.<\/li>\n<\/ul>\n\n\n\n
Arch Linux:<\/p>\n\n\n\n
pacman -S bash-language-server lua-language-server pyright<\/code><\/pre>\n\n\n\nOther distributions\/OSes:<\/p>\n\n\n\n
pip install pyright\nnpm i -g bash-language-server\nbrew install lua-language-server\nport install lua-language-server<\/code><\/pre>\n\n\n\nAfter installing the servers, you need to set up Key Bindings and Highlights and then server configurations.<\/p>\n\n\n\n
Set up key bindings in neovim-lsp<\/h2>\n\n\n\n
First, you need to create a file
~\/.config\/nvim\/plug-config\/lspconfig.lua<\/code>. Now, you need to populate it with configuration. In the very end, I will show you how to ‘source’ it in yourinit.vim<\/code>. Only after that, you will see any result.<\/p>\n\n\n\nIn the file
~\/.config\/nvim\/plug-config\/lspconfig.lua<\/code>, first, create anon_attach<\/code> function, then put your keybindings into it:<\/p>\n\n\n\nlocal on_attach = function(client, bufnr)\n local opts = { noremap = true, silent = true }\n KEY_BINDING_1\n KEY_BINDING_2\nend<\/code><\/pre>\n\n\n\nWhere, <\/p>\n\n\n\n
- \n
- KEY_BINDING_1, 2, … will be replaced by your keybindings.<\/li>\n\n\n\n
opt<\/code> variable will be used in setting up your keybindings.<\/li>\n\n\n\n- Putting the key-bindings inside the
on_attach<\/code> function makes sure that these <\/strong>key-bindings are only created when there is any Language Server attached to the neovim. In our example, we will be configuring the servers only for lua, bash, and python. So, when you open any file with filetypes other than lua, bash and python, these key-bindings will not take any action.<\/li>\n\n\n\n- You can refer to neovim’s help page using
:help nvim_buf_set_keymap()<\/code> for more information.<\/li>\n<\/ul>\n\n\n\nNow, I will help you populate your
on_attach<\/code> function with the necessary key bindings.<\/p>\n\n\n\nSymbols in nvim-lsp<\/h3>\n\n\n\n
Symbols are special keywords in your code such as variables, functions, etc. To get a list of the symbols, execute the command
:lua vim.lsp.buf.document_symbol()<\/code>.<\/p>\n\n\n\nTo bind the command with the key
<leader>ls<\/code>, put the following code inside youron_attach<\/code> function:<\/p>\n\n\n\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>ls', '<cmd>lua vim.lsp.buf.document_symbol()<CR>', opts)<\/code><\/pre>\n\n\n\nDefinition and Declaration in nvim lsp<\/h3>\n\n\n\n
Definition<\/strong>: When you put your cursor on any ‘symbol’ and execute the vim command
lua vim.lsp.buf.definition()<\/code>, your cursor will move to the definition of the symbol. This is quite handy for big projects spread over a large number of files and lines.<\/p>\n\n\n\nDeclaration<\/strong> (
:lua vim.lsp.buf.declaration()<\/code>): many servers do not support the Declaration. Most of the time, Definition is enough.<\/p>\n\n\n\nTo bind the above definition and declaration command with the keys
<leader>ld<\/code> and<leader>lD<\/code>, put the following code inside youron_attach<\/code> function:<\/p>\n\n\n\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>lD', '<cmd>lua vim.lsp.buf.declaration()<CR>', opts)\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>ld', '<cmd>lua vim.lsp.buf.definition()<CR>', opts)<\/code><\/pre>\n\n\n\nHover information in nvim lsp<\/h3>\n\n\n\n
Hover information gives you a help document in a floating window when you ‘hover’ your cursor on any special keyword. For example, in bash language, hovering on
find<\/code> command will give you find’s man page, in python language, hovering onprint()<\/code> will give you short information about the print function.<\/p>\n\n\n\n![\"hover](\"https:\/\/i0.wp.com\/smarttech101.com\/wp-content\/uploads\/2022\/06\/nvim-lsp-hover.png?resize=731%2C458&ssl=1\")
fig 1: hover in nvim lsp: just put your cursor on any symbol (here path<\/code>) and execute the hover command to get the hover information.<\/figcaption><\/figure>\n\n\n\nTo bind the hover command
:lua vim.lsp.buf.hover()<\/code> with the key<leader>lk<\/code>, put the following code in youron_attach<\/code> function:<\/p>\n\n\n\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>lk', '<cmd>lua vim.lsp.buf.hover()<CR>', opts)<\/code><\/pre>\n\n\n\nPlease note that “hovering” in neovim is slightly different. Here, you first need to put your cursor instead of just hover on the symbol and then press
<leader>lk<\/code>. Press this shortcut key again and you will reach into the floating ‘window’. To get out of the floating window, quit (:q<\/code>) as usual.<\/p>\n\n\n\nImplementation in nvim lsp<\/h3>\n\n\n\n
Executing the neovim command
:lua vim.lsp.buf.implementation()<\/code> on any symbol will list all the implementations<\/strong> for the symbol under the cursor in the quickfix window. <\/p>\n\n\n\nHowever, if your language server does not support this you might see the message
method textDocument\/implementation is not supported by any of the servers registered for the current buffer<\/code> at the bottom of your neovim. For your information, the bash-language-server, lua-language-server, and pyright do not support implementations<\/a>.<\/p>\n\n\n\nTo bind this command with the key
<leader>lI<\/code>, put the following code in yourattach_function<\/code>:<\/p>\n\n\n\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>lI', '<cmd>lua vim.lsp.buf.implementation()<CR>', opts)<\/code><\/pre>\n\n\n\nSignature help in nvim lsp<\/h3>\n\n\n\n
Signature help shows information about the parameters of your function\/method in a floating window. For example, suppose you have defined a function with a list of parameters (or variables). When you start to type the parameters’ values one after another, some helpful information will be shown in a floating window.<\/p>\n\n\n\n
![\"signature](\"https:\/\/i0.wp.com\/smarttech101.com\/wp-content\/uploads\/2022\/06\/nvim-lsp-signature-help.png?resize=929%2C382&ssl=1\")
fig 2: signature help in nvim lsp<\/figcaption><\/figure>\n\n\n\n To bind the signature help command
:lua vim.lsp.buf.signature_help()<\/code> with the key<leader>lsh<\/code>, use the following code in youron_attach<\/code> function:<\/p>\n\n\n\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>lsh', '<cmd>lua vim.lsp.buf.signature_help()<CR>', opts)<\/code><\/pre>\n\n\n\nHowever, personally, I find it less useful than using another plug-in
hrsh7th\/cmp-nvim-lsp-signature-help<\/code>. The plug-in gives the signature-help in the floating window without using any shortcut key. On top of that, the plug-in also boaldens the variable under consideration (in figure 2,var2<\/code> is shown in bold in the floating window as I am about to write its value). I will cover more about signature-help in the next article on nvim-lsp autocompletion<\/a>.<\/p>\n\n\n\nWorkspace in nvim lsp<\/h3>\n\n\n\n
A “workspace<\/strong>” is the collection of one or more folders that are opened in your window (source: Workspace in vscode<\/a>).<\/p>\n\n\n\n
To have keybindings for add, remove, and list workspaces, use the following code in your
on_attach<\/code> function:<\/p>\n\n\n\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>lwa', '<cmd>lua vim.lsp.buf.add_workspace_folder()<CR>', opts)\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>lwr', '<cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>', opts)\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>lwl', '<cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>', opts)<\/code><\/pre>\n\n\n\nRename symbols in nvim lsp<\/h3>\n\n\n\n
The command
:lua vim.lsp.buf.rename()<\/code> only renames<\/strong> all references to the symbol under the cursor. It does not rename the string in other places such as comments.<\/p>\n\n\n\nTo bind this command with the key
<leader>lr<\/code>, put the following code in youron_attach<\/code> function:<\/p>\n\n\n\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>lr', '<cmd>lua vim.lsp.buf.rename()<CR>', opts)<\/code><\/pre>\n\n\n\nCode actions in nvim lsp<\/h3>\n\n\n\n
When you write your projects, you might encounter errors\/warnings. Code actions in that case are available suggestions to fix\/remove these errors and warnings. Not all language servers provide this service.<\/p>\n\n\n\n
To bind the key
<leader>lc<\/code> with the command:lua vim.lsp.buf.code_action()<\/code>, use the following code in youron_attach<\/code> function:<\/p>\n\n\n\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>lc', '<cmd>lua vim.lsp.buf.code_action()<CR>', opts)<\/code><\/pre>\n\n\n\nNow press
<leader>lc<\/code> on any symbol\/line with an error\/warning, it would show you possible code actions<\/strong> (like how to solve\/remove the error\/warning) you can do. It gives a list of actions in command line mode and you have to enter a number to choose the action.<\/p>\n\n\n\n![\"code](\"https:\/\/i0.wp.com\/smarttech101.com\/wp-content\/uploads\/2022\/06\/nvim-lsp-code-action.png?resize=731%2C458&ssl=1\")
fig 3: code actions in nvim-lsp (shown at the bottom)<\/figcaption><\/figure>\n\n\n\n Sometimes, code actions are available even if there is no error\/warning\/information\/hint. In that case, you can show a lightbulb using
kosayoda\/nvim-lightbulb<\/code> plug-in.<\/p>\n\n\n\nList all references to the symbol using nvim lsp<\/h3>\n\n\n\n
Nvim lsp command
:lua vim.lsp.buf.references()<\/code> on any symbol under the cursor lists all the references<\/strong> to the symbol in a quickfix window.<\/p>\n\n\n\n![\"references](\"https:\/\/i0.wp.com\/smarttech101.com\/wp-content\/uploads\/2022\/06\/nvim-lsp-references-1.png?resize=731%2C458&ssl=1\")
fig 4: references to the symbol filename<\/code> in the quickfix window shown in red.<\/figcaption><\/figure>\n\n\n\nTo bind this command with
<leader>lR<\/code>, put the following code in youron_attach<\/code> function:<\/p>\n\n\n\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>lR', '<cmd>lua vim.lsp.buf.references()<CR>', opts)<\/code><\/pre>\n\n\n\nFormatting in nvim lsp<\/h3>\n\n\n\n
Formatting removes\/enters unnecessary spaces, newline characters, etc., and thus makes your code look soothing to the eyes.<\/p>\n\n\n\n
To bind the formatting command
:lua vim.lsp.buf.formatting()<\/code> with the key<leader>lf<\/code>, use the following code in youron_attach<\/code> function:<\/p>\n\n\n\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>lf', '<cmd>lua vim.lsp.buf.formatting()<CR>', opts)<\/code><\/pre>\n\n\n\nHowever, only a few language servers (ex – lua-language-server) provide formatting but others (ex – bash-language-server) don’t. So, use a plug-in called null-ls which kind of merges formatters with language servers. For example, bash-language-server does not provide formatting. Therefore by using
null-ls<\/code>, you can “bring” the formatting ability into this from a separate formatter shfmt<\/a>. To use it, head over to my in-depth article on null-ls<\/a>.<\/p>\n\n\n\nNote 1:<\/strong> Please note that the formatting command is a little different in nvim v 0.8:<\/p>\n\n\n\n
-- 0.7\nvim.lsp.buf.formatting_sync(nil, 2000) -- 2 seconds\n\n-- 0.8\nvim.lsp.buf.format({ timeout_ms = 2000 }) -- 2 seconds<\/code><\/pre>\n\n\n\nGet information about language servers attached to neovim<\/h3>\n\n\n\n
The neovim command
LspInfo<\/code> prints detected filetype, attached language servers, root directory, etc. in a floating window.<\/p>\n\n\n\nTo bind this command with the key
<leader>li<\/code>, put the following code in youron_attach<\/code> function:<\/p>\n\n\n\nvim.api.nvim_buf_set_keymap(bufnr, 'n', '<leader>li', '<cmd>LspInfo<CR>', opts)<\/code><\/pre>\n\n\n\nHighlight symbol under the cursor using nvim lsp<\/h2>\n\n\n\n
When you put your cursor on any one symbol, the symbol is highlighted everywhere.<\/p>\n\n\n\n
![\"highlight](\"https:\/\/i0.wp.com\/smarttech101.com\/wp-content\/uploads\/2022\/06\/highlight-nvim-lsp-1.png?resize=731%2C458&ssl=1\")
fig 5: highlight your symbol filename<\/code> under the cursor<\/figcaption><\/figure>\n\n\n\nTo highlight the symbol under the cursor, put the following code in the same file
~\/.config\/nvim\/plug-config\/lspconfig.lua<\/code>. Please note that these lines should go into theon_attach<\/code> function.<\/strong><\/p>\n\n\n\nif client.resolved_capabilities.document_highlight then\n vim.cmd [[\n hi! LspReferenceRead cterm=bold ctermbg=235 guibg=LightYellow\n hi! LspReferenceText cterm=bold ctermbg=235 guibg=LightYellow\n hi! LspReferenceWrite cterm=bold ctermbg=235 guibg=LightYellow\n ]]\n vim.api.nvim_create_augroup('lsp_document_highlight', {})\n vim.api.nvim_create_autocmd({ 'CursorHold', 'CursorHoldI' }, {\n group = 'lsp_document_highlight',\n buffer = 0,\n callback = vim.lsp.buf.document_highlight,\n })\n vim.api.nvim_create_autocmd('CursorMoved', {\n group = 'lsp_document_highlight',\n buffer = 0,\n callback = vim.lsp.buf.clear_references,\n })\n end<\/code><\/pre>\n\n\n\nAs you can see I am using the
if..end<\/code> condition for highlighting. This prevents neovim from asking the language server to highlight your symbol if the server does not have this ability.<\/p>\n\n\n\nEdit 15\/11\/2022: For Neovim 0.8 or above, use
client.server_capabilities.documentHighlightProvider<\/code><\/strong> instead ofclient.resolved_capabilities.document_highlight<\/code><\/strong>.<\/p>\n\n\n\n\ud83d\udcd3Note<\/strong>: You can change the
ctermbg<\/code> and\/orguibg<\/code> to get the appropriate highlighting color. Similarly, you can also use italics instead of bold, provided your terminal supports it.<\/p>\n\n\n\n- Putting the key-bindings inside the
- However, If you cannot install it using the above method, just search on Google, head over to the official sites <\/strong>of these servers, and follow the recommended methods.<\/li>\n<\/ul>\n\n\n\n
- Plug-in
- Configure each server separately in nvim-lsp<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n
- Hover information in neovim lsp<\/a><\/li>\n\n\n\n
- Install useful plug-ins for nvim lsp<\/a><\/li>\n\n\n\n
- Nvim lsp: autocompletion – mapping, snippets, fuzzy search, and icons<\/a><\/li>\n<\/ol>\n\n\n\n