TLDR: Here is how final result will look like (that small thing at bottom right):

Recently, I really fell in love with FZF. FZF is really awesome fuzzy finder for command-line. I started to use to navigate basically everything, starting with searching through zsh history and ending with controlling my music player with it. FZF looks like this (taken from official repository, because I am too lazy to make pretty gifs):

And in between, there is Vim. I am using FZF and fzf.vim plugins for Vim to:

  • Navigate buffer
  • Search in tags
  • Open files
  • Search in vim documentation
  • Search through all text files in my current directory (not using this very much, but it is neat how fast it is with ripgrep set as FZF grepping program)

And now, I am also using it for completion instead of default Vim completion popup. Awesome, right? I agree that it is maybe a bit overkill and maybe I will switch back to completion popup, but right now I am super happy with it (and spent too many hours making it work to just dump it) so I decided to write shitty blog post with my bad english about how awesome it is and how awesome AM I.

Requirements

  • FZF (of course)
  • completor.vim (this one is optional, and required only for context-sensitive completion)

Let’s get started

So, here is the custom completion function:

let g:fuzzyfunc = &omnifunc

function! FuzzyCompleteFunc(findstart, base)
  let Func = function(get(g:, 'fuzzyfunc', &omnifunc))
  let results = Func(a:findstart, a:base)

  if a:findstart
    return results
  endif

  if type(results) == type({}) && has_key(results, 'words')
    let l:words = []
    for result in results.words
      call add(words, result.word . ' ' . result.menu)
    endfor
  elseif len(results)
    let l:words = results
  endif

  if len(l:words)
    let result = fzf#run({ 'source': l:words, 'down': '~40%', 'options': printf('--query "%s" +s', a:base) })

    if empty(result)
      return [ a:base ]
    endif

    return [ split(result[0])[0] ]
  else
    return [ a:base ]
  endif
endfunction

This function first gathers results from calling defined g:fuzzyfunc (that we set to vim omnifunc) and then sends it to fzf#run function, that is function from fzf plugin for vim and this function will open small FZF split at bottom what will be used as filter for our results. Then it returns single filtered result from this function.

Now, to actually use this, we can set our complete function as completefunc:

set completefunc=FuzzyCompleteFunc
set completeopt=menu

completeopt modification is needed to tell vim to automatically match completion if there is only one result (and our custom completion function will return only one result). This change will make FZF with completion trigger after pressing Control-X and then Control-U. But, this option will not work with completor.vim (will talk about this later), because it is setting it’s own completefunc, so we need to make small hack. So second (and better) option is to create your own trigger (as I did in my own vimrc) and not mess with completefunc and completeopt and leave them free for other plugins (like completor.vim):

function! FuzzyFuncTrigger()
  setlocal completefunc=FuzzyCompleteFunc
  setlocal completeopt=menu
  call feedkeys("\<c-x>\<c-u>", 'n')
endfunction

imap <c-x><c-j> <c-o>:call FuzzyFuncTrigger()<cr>

This will add new trigger, Control-X and then Control-J that will trigger FZF completion. This is nice and stuff, but triggerring completion with Control-X and Control-J… triggers me. But auto popups too, so let’s make completion to be triggered by TAB:

function! TabComplete()
  let col = col('.') - 1

  if !col || getline('.')[col - 1] !~# '\k'
    call feedkeys("\<tab>", 'n')
    return
  endif

  call feedkeys("\<c-x>\<c-j>")
endfunction

inoremap <silent> <tab> <c-o>:call TabComplete()<cr>

If you chose to use completefunc option instead of custom trigger with Control-X and then Control-J, then just replace <c-j> with <c-u> in above snippet. And now, let’s try to integrate this with completor.vim.

Using FZF with completor.vim

So first, you are maybe asking what is completor.vim? In short it is some sort of async completion thingy for Vim. Faster completion, no lags and stuff. But this is not why I chose it. I chose it because it have awesome completion function that I can wrap in FZF. This completion function is deciding if it will run file completion, buffer completion, it’s internal async completion for supported languages or omnicompletion. So, that is why. So, just go and get it. Or just keep using omnifunc.

So, thanks to previous awesome impletentation of FuzzyCompleteFunc all we need to do is adjust g:fuzzyfunc:

let g:fuzzyfunc = 'completor#completefunc'

completor#completefunc is internal completion function of completor.vim that is returning results in same format as omnifunc, but they are context sensitive (as I wrote earlier).

Final words

Now, place whatever you want from here to your .vimrc, and we are done. Yes, we are done, really.

I will try to write more articles about some cool random stuff I am doing with Vim and Tmux (if I will have time) so stay tuned (or not, whatever).

Also, here are my dotfiles that contains everything mentioned in this post and a lot more and here is my .vimrc

EDIT: Updated post with better completion function and with images (woohooo)