Deoplete.nvim: Suggested manual_complete Tab mapping example prevents tab spacing

[ajcrites]

Problems summary

The documentation provides an example of disabling auto complete and using <Tab> to manually complete:

inoremap <silent><expr> <Tab>
    \ pumvisible() ? "\<C-n>" : deoplete#manual_complete()

However, this prevents the <Tab> character from actually being used for spacing

Expected

Provide example that does not clobber <Tab> functionality on failure, or allow manual complete to be triggered by appropriate pattern (e.g. not at the start of a line or under a space).

Environment Information

• OS: OS-X
• nvim-python-doctor result or :CheckHealth result(neovim ver.0.1.5-452+):
  https://github.com/tweekmonster/nvim-python-doctor

Checking: Python 2
  Executable: /usr/bin/python2.7
  Python Version: 2.7.10
  python2.7-neovim Version: not found (unknown)
  Messages:
    * Warning: No Python interpreter was found with the neovim module.  Using
      the first available for diagnostics.
    * provider/pythonx: Could not load Python 2:
      python2 not found in search path or not executable.
      /usr/bin/python2.7 does have not have the neovim module installed. See
      ":help nvim-python".
      /usr/bin/python2.6 does have not have the neovim module installed. See
      ":help nvim-python".
      /usr/bin/python does have not have the neovim module installed. See
      ":help nvim-python".
    * Warning: "g:python_host_prog" is not set.  Searching for python2.7 in
      the environment.
    * Error: Neovim Python client is not installed.

Checking: Python 3
  Executable: /usr/local/bin/python3
  Python Version: 3.5.2
  python3-neovim Version: 0.1.9 (up to date)
  Messages:
    * Warning: "g:python3_host_prog" is not set.  Searching for python3 in
      the environment.

Checking: Remote Plugins
  Status: Out of date
  Messages:
    * ".dein" is not registered.
    * Run :UpdateRemotePlugins

Provide a minimal init.vim with less than 50 lines (Required!)

set t_Co=256
call pathogen#infect()

set nocompatible     " Not like Vi
set autoread         " detect when file is changed
set ttyfast          " faster redraw
set nolazyredraw     " don't redraw when executing macros
set autoindent       " autoidentation on
set smartindent      " smartindentation on
set showmatch        " blink back to closing bracket (using % key)
set shell=$SHELL
set title            " terminal title
set background=dark  " highlighting depends on background color (dark or light)
set nowrapscan       " turn off search wrapping
set ignorecase       " ignore case in search
set smartcase        " consider case only when typing Uppercase
set hlsearch         " highlight search pattern
set vb t_vb=         " don't notify (no audio/visual bell)
set showmode         " display mode INSERT/REPLACE/...
set scrolloff=3      " dont let the curser get too close to the edge
set laststatus=2     " laststatus:  show status line?  Yes, always!
set nonumber         " no line numbers
set expandtab        " Expand Tabs (pressing Tab inserts spaces)
set backspace=indent,eol,start   " allow backspacing over everything in insert mode
set list listchars=tab:>-        " visual display of tabs
set complete+=k      " dictionary scanning
set bs=2             " backspace ???
set exrc
set secure
set nofoldenable     " folding is over!
retab                " force all Tab characters to match current Tab preferences
filetype plugin on   " idk what this does, but it seems important
syntax on            " Enable syntax highlighting
set omnifunc=syntaxcomplete#Complete

set runtimepath^=~/.config/nvim/dein/repos/github.com/Shougo/dein.vim
call dein#begin(expand('~/.config/nvim/dein'))

call dein#add('Shougo/dein.vim')
call dein#add('Shougo/deoplete.nvim')
call dein#add('carlitux/deoplete-ternjs')
call dein#add('tweekmonster/nvim-checkhealth')

call dein#end()

let g:deoplete#disable_auto_complete = 1
let b:SuperTabDisabled = 1
inoremap <silent><expr> <Tab>
        \ pumvisible() ? "\<C-n>" : deoplete#manual_complete()
autocmd CompleteDone * pclose!
let g:SuperTabDefaultCompletionType = "<c-n>"

The reproduce ways from neovim starting (Required!)

Update your vim configuration with the inoremap for <Tab> from the example in the docs:

inoremap <silent><expr> <Tab>
    \ pumvisible() ? "\<C-n>" : deoplete#manual_complete()

Notice that when you <Tab> at the start of a line or with space under the cursor, it does not indent.

[Shougo]

Fixed.

[bnjmn]

Use this instead:

inoremap <silent><expr> <TAB>
    \ pumvisible() ? "\<C-n>" :
    \ <SID>check_back_space() ? "\<TAB>" :
    \ deoplete#mappings#manual_complete()
function! s:check_back_space() abort "{{{
    let col = col('.') - 1
    return !col || getline('.')[col - 1]  =~ '\s'
endfunction"}}}

[ahstro]

NB for people potentially tearing their hair out: Using <tab> for completion is interfered with by UltiSnip's let g:UltiSnipsExpandTrigger, which defaults to <tab>. Set it to something else and you're good to go.

[andresnmejiaa]

Is there any way to change this solution so that it first checks to see if there is a snippet for Ultisnips, and then if there is call that snippet completion before deoplete?

[Shougo]

Unfortunately I don't know about Ultisnips API.
You can ask it in Ultisnips issues.

[Shougo]

You can use the snippet for it.

Note: I have recovered it from reddit.

inoremap <silent> <tab> <c-r>=MyUltisnipsJump()<cr>

function! MyUltisnipsJump() abort
  if pumvisible()
    call UltiSnips#ExpandSnippet()
    if g:ulti_expand_res == 1
      return ''
    endif
    return "\<C-y>"
  endif
  call UltiSnips#JumpForwards()
  if g:ulti_jump_forwards_res == 1
    return ''
  endif
  call UltiSnips#ExpandSnippet()
  if g:ulti_expand_res == 1
    return ''
  endif

  return "\<tab>"
endfunction

[Shougo]

It seems ugly hack though.

I use neosnippet instead. If you really integrate with deoplete, neosnippet is recommended.