UltiSnips and YouCompleteMe

I have bundles ultisnips and youcompleteme installed on my macvim. The problem is that ultisnips doesn't work because tab is bound by ycm. I tried putting let g:UltiSnipsExpandTrigger = "<s-tab>" so that I can trigger the snippet completion with shift-tab, but it doesn't work for some unknown reason. I could use caps as the trigger, but so far I've found no way to do that.

Do any of you use those two add-ons together? What can I do to make shift-tab work? Can you recommend another key to trigger snippets?

Another option is using the SuperTab plugin:

" if you use Vundle, load plugins:
Bundle 'ervandew/supertab'
Bundle 'Valloric/YouCompleteMe'
Bundle 'SirVer/ultisnips'

" make YCM compatible with UltiSnips (using supertab)
let g:ycm_key_list_select_completion = ['<C-n>', '<Down>']
let g:ycm_key_list_previous_completion = ['<C-p>', '<Up>']
let g:SuperTabDefaultCompletionType = '<C-n>'

" better key bindings for UltiSnipsExpandTrigger
let g:UltiSnipsExpandTrigger = "<tab>"
let g:UltiSnipsJumpForwardTrigger = "<tab>"
let g:UltiSnipsJumpBackwardTrigger = "<s-tab>"

Here YouCompleteMe is bound to a different combination Ctrln, but then that combination is bound to tab through SuperTab. UltiSnips and SuperTab play nice together, so you can then just bind UltiSnips to tab directly and everything will work out.

Try this suggestion on a page from the YouCompleteMe issue tracker. In your .vimrc:

let g:UltiSnipsExpandTrigger="<c-j>"

While this setting will make expanding a snippet share the default mapping for jumping forward within a snippet, it simulates TextMates' behavior as mentioned in the UltiSnips help tags.

Since I've mapped my Caps Lock key to Ctrl, this mapping works pretty smoothly.

copy the following code to your vimrc, and enjoy. This function will handle all issues between YCM and UltiSnips.

function! g:UltiSnips_Complete()
    call UltiSnips#ExpandSnippet()
    if g:ulti_expand_res == 0
        if pumvisible()
            return "\<C-n>"
        else
            call UltiSnips#JumpForwards()
            if g:ulti_jump_forwards_res == 0
               return "\<TAB>"
            endif
        endif
    endif
    return ""
endfunction

au BufEnter * exec "inoremap <silent> " . g:UltiSnipsExpandTrigger . " <C-R>=g:UltiSnips_Complete()<cr>"
let g:UltiSnipsJumpForwardTrigger="<tab>"
let g:UltiSnipsListSnippets="<c-e>"
" this mapping Enter key to <C-y> to chose the current highlight item 
" and close the selection list, same as other IDEs.
" CONFLICT with some plugins like tpope/Endwise
inoremap <expr> <CR> pumvisible() ? "\<C-y>" : "\<C-g>u\<CR>"

i have this in my vimrc

"" YouCompleteMe
let g:ycm_key_list_previous_completion=['<Up>']

"" Ultisnips
let g:UltiSnipsExpandTrigger="<c-tab>"
let g:UltiSnipsListSnippets="<c-s-tab>"

thats what i did on my first try, but i misspelled UltiSnips with Ultisnips.. oh well, worked out in the end!

I personally chose to not use <tab> with YouCompleteMe but navigate it manually.

So I added this to my .vimrc:

let g:ycm_key_list_select_completion=[]
let g:ycm_key_list_previous_completion=[]

which simply disables the tab key for YCM. Instead you use the movement keys (arrows or CTRL-N/CTRL-P) and select the entry with CR. UltiSnips works default with tab.

Just putting together answers by Michaelslec, Joey Liu and along with solutions I found in this issue thread and this guy's vimrc, I now have this which solved pretty much all problems.

function! g:UltiSnips_Complete()
  call UltiSnips#ExpandSnippet()
  if g:ulti_expand_res == 0
    if pumvisible()
      return "\<C-n>"
    else
      call UltiSnips#JumpForwards()
      if g:ulti_jump_forwards_res == 0
        return "\<TAB>"
      endif
    endif
  endif
  return ""
endfunction

function! g:UltiSnips_Reverse()
  call UltiSnips#JumpBackwards()
  if g:ulti_jump_backwards_res == 0
    return "\<C-P>"
  endif

  return ""
endfunction


if !exists("g:UltiSnipsJumpForwardTrigger")
  let g:UltiSnipsJumpForwardTrigger = "<tab>"
endif

if !exists("g:UltiSnipsJumpBackwardTrigger")
  let g:UltiSnipsJumpBackwardTrigger="<s-tab>"
endif

au InsertEnter * exec "inoremap <silent> " . g:UltiSnipsExpandTrigger     . " <C-R>=g:UltiSnips_Complete()<cr>"
au InsertEnter * exec "inoremap <silent> " .     g:UltiSnipsJumpBackwardTrigger . " <C-R>=g:UltiSnips_Reverse()<cr>"

Although I know this post is a little old, I have my own function that is a little more optimized than the one given above:

function! g:UltiSnips_Complete()
  call UltiSnips#ExpandSnippetOrJump()
  if g:ulti_expand_or_jump_res == 0
    if pumvisible()
      return "\<C-N>"
    else
      return "\<TAB>"
    endif
  endif
    
  return ""
endfunction

Of course, if you just keep the settings that Joey Liu provided and then just use this function everything will work just perfectly!

EDIT: Also, I use another function to increase back-stepping functionality between YouCompleteMe and UltiSnips. I'll show you what I mean:

function! g:UltiSnips_Reverse()                                                                                               
  call UltiSnips#JumpBackwards()                                                                                              
  if g:ulti_jump_backwards_res == 0        
    return "\<C-P>"                                                                                                           
  endif                                                                                                                       

  return ""                                                                                                                   
endfunction

Then just put this in your .vimrc:

au BufEnter * exec "inoremap <silent> " . g:UltiSnipsJumpBackwardTrigger . " <C-R>=g:UltiSnips_Reverse()<cr>"

As well as let g:UltiSnipsJumpBackwardTrigger="<s-tab>" and your set!

Based on Siegfried's answer, I am using the following which seems more natural:

let g:ycm_key_list_select_completion = ['<C-j>']
let g:ycm_key_list_previous_completion = ['<C-k>']

let g:UltiSnipsExpandTrigger = "<C-l>"
let g:UltiSnipsJumpForwardTrigger = "<C-j>"
let g:UltiSnipsJumpBackwardTrigger = "<C-k>"

I also use the c-hjkl bindings somewhere else (switching from a pane to another), but that would only be in normal mode, so there's no problem.

I use both of them together. By default YouCompleteMe binds <Tab> and <Down> to select the next completion item and also <S-Tab> and <Up> to select the previous completion item. You can change the YouCompleteMe bindings with the g:ycm_key_list_select_completion and g:ycm_key_list_previous_completion options. Note that the names of these options were recently changed when the option was changed from a single string to a list of strings.

While Many answer works fine in this post, I just want to say that the problem is caused by key binding collision between YCM and UltiSnip, while YCM support UltiSnip snippets by default, it takes the default UltiSnip expand trigger <tab> as its completion select key, so UltiSnip snippets will not be expaned by <tab>. Give them different key binding will solve the problem, I personally use <c-n and <c-p> for YCM and use the default <tab> for UltiSnip. You can get more details with help youcompleteme doc in vim.

I installed the UltiSnips plugin after the YouCompleteMe plugin so I thought they were conflicting, but in reality I had something more interfering:

set paste

Make sure to remove that from .vimrc if it's present.

I use ; to expand UltiSnips, it's so nifty for me

let g:UltiSnipsExpandTrigger = ";"

I use kj. This is what is in my .vimrc:

let g:UltisnipsExpandTrigger="kj".

It rarely happens that I run into word that has kj in it. If this is the case I would just wait a couple of seconds after typing k and that type j.

As mentioned by others, mapping C-j to ultisnips works great.
let g:UltiSnipsExpandTrigger="<c-j>"

Now, if you go a bit further and install xcape and use
xcape -e "Shift_L=Control_R|J"

You unleash the power of using just the shift key for utlitsnips.