completion-nvim

completion-nvim is an auto completion framework that aims to provide a better completion experience with neovim's built-in LSP. Other LSP functionality is not supported.

Features

• Asynchronous completion using the libuv api.
• Automatically open hover windows when popupmenu is available.
• Automatically open signature help if it's available.
• Snippets integration with UltiSnips and Neosnippet and vim-vsnip.
• Apply additionalTextEdits in LSP spec if it's available.
• Chain completion support inspired by vim-mucomplete

Demo

Demo using sumneko_lua

Prerequisites

• Neovim nightly
• You should set up your language server of choice with the help of nvim-lsp

Install

• Install with any plugin manager by using the path on GitHub.

Plug 'haorenW1025/completion-nvim'

Setup

• completion-nvim requires several autocommands set up to work properly. You should set it up using the on_attach function like this.

lua require'nvim_lsp'.pyls.setup{on_attach=require'completion'.on_attach}

• Change pyls to whichever language server you're using.
• If you want completion-nvim to be set up for all buffers instead of only being used when lsp is enabled, call the on_attach function directly:

" Use completion-nvim in every buffer
autocmd BufEnter * lua require'completion'.on_attach()

NOTE It's okay to set up completion-nvim without lsp. It will simply use another completion source instead(Ex: snippets).

Supported Completion Source

• built-in sources

  • lsp: completion source for neovim's built-in LSP.
  • snippet: completion source for snippet.
  • path: completion source for path from current file.

• ins-complete sources

  • See :h ins-completion and wiki

• external sources

  • completion-buffers: completion for buffers word.
  • completion-treesitter: treesitter based completion sources.
  • vim-dadbod-completion: completion sources for vim-dadbod.

Configuration

Recommended Setting

" 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>"

" Set completeopt to have a better completion experience
set completeopt=menuone,noinsert,noselect

" Avoid showing message extra message when using completion
set shortmess+=c

Enable/Disable auto popup

• By default auto popup is enabled, turn it off by

let g:completion_enable_auto_popup = 0

• Or you can toggle auto popup on the fly by using command CompletionToggle
• You can manually trigger completion with mapping key by

inoremap <silent><expr> <c-p> completion#trigger_completion() "map <c-p> to manually trigger completion

• Or you want to use <Tab> as trigger keys

function! s:check_back_space() abort
    let col = col('.') - 1
    return !col || getline('.')[col - 1]  =~ '\s'
endfunction

inoremap <silent><expr> <TAB>
  \ pumvisible() ? "\<C-n>" :
  \ <SID>check_back_space() ? "\<TAB>" :
  \ completion#trigger_completion()

Enable Snippets Support

• By default other snippets source support are disabled, turn them on by

" possible value: 'UltiSnips', 'Neosnippet', 'vim-vsnip'
let g:completion_enable_snippet = 'UltiSnips'

• Support UltiSnips and Neosnippet and vim-vsnip

LSP Based Snippet parsing

• Some language server have snippet support but neovim couldn't handle that for now, completion-nvim can integrate with other LSP snippet parsing plugin for this support.

• Right now only support vim-vsnip(require vim-vsnip-integ), it should work out of the box if you have vim-vsnip and vim-vsnip-integ installed.

Chain Completion Support

• completion-nvim supports chain completion, which use other completion sources and ins-completion as a fallback for lsp completion.

• See wiki for details on how to set this up.

Changing Completion Confirm key

• By default <CR> is used to confirm completion and expand snippets, change it by

let g:completion_confirm_key = "\<C-y>"

• Make sure to use " " and add escape key \ to avoid parsing issues.
• If the confirm key has a fallback mapping, for example when using the auto pairs plugin, it maps to <CR>. You can avoid using the default confirm key option and use a mapping like this instead.

let g:completion_confirm_key = ""
imap <expr> <cr>  pumvisible() ? complete_info()["selected"] != "-1" ?
                 \ "\<Plug>(completion_confirm_completion)"  : "\<c-e>\<CR>" :  "\<CR>"

Enable/Disable auto hover

• By default when navigating through completion items, LSP's hover is automatically called and displays in a floating window. Disable it by

let g:completion_enable_auto_hover = 0

Enable/Disable auto signature

• By default signature help opens automatically whenever it's available. Disable it by

let g:completion_enable_auto_signature = 0

Sorting completion items

• You can decide how your items being sorted in the popup menu. The default value is "alphabet", change it by

" possible value: "length", "alphabet", "none"
let g:completion_sorting = "length"

• If you don't want any sorting, you can set this value to "none".

Matching Strategy

• There are three different kind of matching technique implement in completion-nvim: substring, fuzzy or exact.

• You can specify a list of matching strategy, completion-nvim will loop through the list and assign priority from high to low. For example

let g:completion_matching_strategy_list = ['exact', 'substring', 'fuzzy']

NOTE Fuzzy match highly dependent on what language server you're using. It might not work as you expect on some language server.

• You can also enable ignore case matching by

g:completion_matching_ignore_case = 1

Trigger Characters

• By default, completion-nvim respect the trigger character of your language server, if you want more trigger characters, add it by

let g:completion_trigger_character = ['.', '::']

NOTE use :lua print(vim.inspect(vim.lsp.buf_get_clients()[1].server_capabilities.completionProvider.triggerCharacters)) to see the trigger character of your language server.

• If you want different trigger character for different languages, wrap it in an autocommand like

augroup CompletionTriggerCharacter
    autocmd!
    autocmd BufEnter * let g:completion_trigger_character = ['.']
    autocmd BufEnter *.c,*.cpp let g:completion_trigger_character = ['.', '::']
augroup end

Trigger keyword length

• You can specify keyword length for triggering completion, if the current word is less then keyword length, completion won't be triggered.

let g:completion_trigger_keyword_length = 3 " default = 1

NOTE completion-nvim will ignore keyword length if you're on trigger character.

Trigger on delete

• completion-nvim doesn't trigger completion on delete by default because sometimes I've found it annoying. However, you can enable it by

let g:completion_trigger_on_delete = 1

Timer Adjustment

• completion-nvim uses a timer to control the rate of completion. You can adjust the timer rate by

let g:completion_timer_cycle = 200 "default value is 80

Compatibility with diagnostic-nvim

• This plugin only focuses on the completion part of the built-in LSP. If you want similar help with diagnostics (e.g. virtual text, jump to diagnostic, open line diagnostic automatically...), take a look at diagnostic-nvim.

• Both diagnostic-nvim and completion-nvim require setting up via on_attach. To use them together, create a wrapper function like this.

lua << EOF
local on_attach_vim = function()
  require'completion'.on_attach()
  require'diagnostic'.on_attach()
end
require'nvim_lsp'.pyls.setup{on_attach=on_attach_vim}
EOF

Trouble Shooting

• This plugin is in the early stages and might have unexpected issues. Please follow wiki for trouble shooting.
• Feel free to post issues on any unexpected behavior or open a feature request!