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Configuring LSP on NeoVim ​

Posted on 26 May, 2021

Make sure you have NeoVim version >=0.5.5 installed

Necessary stuff ​

vim
" For language server configurations
Plug 'neovim/nvim-lspconfig'

For autocompletion choose either of these choices both seems to be equally good

vim
Plug 'nvim-lua/completion-nvim'

Or

vim
Plug 'hrsh7th/nvim-compe'

For the sake of this guide I have chosen nvim-compe

Installing language servers ​

You would have to manually install the language servers you need.

  1. Install language server pack for python (make sure you are running latest pip and Python 3.6+)

    bash
    pip install 'python-language-server[all]'

    Another alternative to python-language-server is pyright

    bash
    pip3 install pyright

  2. Language server pack for go is maintained by the go team itself. Use go get to install gopls

    bash
    GO111MODULE=on go get golang.org/x/tools/gopls@latest

    Or, You can also use the vim-go plug-in

    vim
    Plug 'fatih/vim-go', { 'do': ':GoUpdateBinaries' }
" run :GoInstallBinaries if setting up first time
" this will also install the languager server for go (gopls) automatically

  3. For bash, install bash-language-server

    bash
    # if you have npm installed
npm i -g bash-language-server
# snap
sudo snap install bash-language-server

Configure keybindings ​

The following boilerplate config can be used as it is

vim
set completeopt=menuone,noselect

" Use <Tab> and <S-Tab> to navigate through popup menu
inoremap <expr> <Tab>   pumvisible() ? "\<C-n>" : "\<Tab>"
inoremap <expr> <S-Tab> pumvisible() ? "\<C-p>" : "\<S-Tab>"

nnoremap <silent> gd <cmd>lua vim.lsp.buf.definition()<CR>
nnoremap <silent> gD <cmd>lua vim.lsp.buf.declaration()<CR>
nnoremap <silent> gr <cmd>lua vim.lsp.buf.references()<CR>
nnoremap <silent> gi <cmd>lua vim.lsp.buf.implementation()<CR>
nnoremap <silent> gh <cmd>lua vim.lsp.buf.hover()<CR>
nnoremap <silent> <C-k> <cmd>lua vim.lsp.buf.signature_help()<CR>
nnoremap <silent> <C-n> <cmd>lua vim.lsp.diagnostic.goto_prev()<CR>
nnoremap <silent> <C-p> <cmd>lua vim.lsp.diagnostic.goto_next()<CR>

" Auto format using LSP on save
autocmd BufWritePre *go,*.py lua vim.lsp.buf.formatting_sync(nil, 100)

Setup nvim-lspconfig ​

vim
" Initialise server packs
lua <<EOF
require'lspconfig'.gopls.setup{}
require'lspconfig'.pyls.setup{}
# or require'lspconfig'.pyright.setup{}
require'lspconfig'.bashls.setup{}
EOF

Setup nvim-compe ​

vim
let g:compe = {}
let g:compe.enabled = v:true
let g:compe.autocomplete = v:true
let g:compe.debug = v:false
let g:compe.min_length = 1
let g:compe.preselect = 'enable'
let g:compe.throttle_time = 80
let g:compe.source_timeout = 200
let g:compe.resolve_timeout = 800
let g:compe.incomplete_delay = 400
let g:compe.max_abbr_width = 100
let g:compe.max_kind_width = 100
let g:compe.max_menu_width = 100
let g:compe.documentation = v:true

let g:compe.source = {}
let g:compe.source.path = v:true
let g:compe.source.buffer = v:true
let g:compe.source.calc = v:true
let g:compe.source.nvim_lsp = v:true
let g:compe.source.nvim_lua = v:true
let g:compe.source.vsnip = v:true
let g:compe.source.ultisnips = v:true
let g:compe.source.luasnip = v:true
let g:compe.source.emoji = v:true

Notice: If you are embedding lua code in your vimscript config, use the following heredoc

lua <<EOF
-- [[ this is lua comment ]]
   lua code
   ...
EOF

After setting up both the plugins open a file whose language server you installed and run :LspInfo to check server diagnostics

Spicy Stuff 🌶️ ​

Below are some plugins which spice up the neovim lsp experience

lspsaga.nvim ​

Richer UI for LSP

vim
Plug 'neovim/nvim-lspconfig'
Plug 'glepnir/lspsaga.nvim'
vim
" lsp provider to find the cursor word definition and reference
nnoremap <silent> gh <cmd>lua require'lspsaga.provider'.lsp_finder()<CR>
" preview definition
nnoremap <silent> gd <cmd>lua require'lspsaga.provider'.preview_definition()<CR>
" show hover doc
nnoremap <silent> K <cmd>lua require('lspsaga.hover').render_hover_doc()<CR>
" scroll down hover doc or scroll in definition preview
nnoremap <silent> <C-f> <cmd>lua require('lspsaga.action').smart_scroll_with_saga(1)<CR>
" scroll up hover doc
nnoremap <silent> <C-b> <cmd>lua require('lspsaga.action').smart_scroll_with_saga(-1)<CR>
" code action
nnoremap <silent><leader>ca <cmd>lua require('lspsaga.codeaction').code_action()<CR>
vnoremap <silent><leader>ca :<C-U>lua require('lspsaga.codeaction').range_code_action()<CR>

lsp_signature ​

Show function signature help as you type

vim
Plug 'ray-x/lsp_signature.nvim'
vim
lua <<EOF
require'lspconfig'.gopls.setup {
    on_attach = function(client)
    require 'lsp_signature'.on_attach(client)
end,
}
EOF

vim-illuminate ​

Highlighting other uses of the current word under the cursor

vim
Plug 'RRethy/vim-illuminate'

After installing make sure you have a language server running, it should work out of the box You can manually enable what files to use illuminate on as well

vim
let g:Illuminate_ftwhitelist = ['vim', 'sh', 'python']

Resources ​

Written while 🙇🏽‍♀️