Use fzf.vim to fuzzy-find available mix commands

fzf-mix.vim

function! g:MixRun(selection) abort
  if !empty(a:selection)
    execute "!mix ".a:selection
  endif
endfunction

function! g:MixFzf(selection = '') abort
  if empty(a:selection)
    call fzf#run(fzf#wrap({
      \ 'source': 'mix help --names',
      \ 'sink': function('g:MixRun'),
      \ 'layout' : {
        \ 'window': {
          \ 'width': 0.95,
          \ 'height': 0.9,
          \ 'relative': v:true,
          \ 'yoffset': 1.0 } },
      \ 'options': "--preview 'mix help {}'"}))
  else
    call MixRun(a:selection)
  endif
endfunction

command! -nargs=* Mix call MixFzf(<q-args>)

" Use FZF: :Mix<cr>
" Direct: :Mix compile<cr>