neovim (deoplete.vim + neosnippet.vim ...)でコード補完とかスニペットとか

一応vimrcを以下のようにするといけた。Mac 10.13.6, vimは8.1

"
"
" neosnippet
"
" you need to add ~/.vim/snippets/[extension].snip for your own snippets
"
"
Plugin 'Shougo/deoplete.nvim'
if !has('nvim')
  Plugin 'roxma/nvim-yarp'
  Plugin 'roxma/vim-hug-neovim-rpc'
endif

Plugin 'Shougo/neosnippet.vim'
Plugin 'Shougo/neosnippet-snippets'

" Plugin key-mappings.
" Note: It must be "imap" and "smap".  It uses <Plug> mappings.
imap <C-k>     <Plug>(neosnippet_expand_or_jump)
smap <C-k>     <Plug>(neosnippet_expand_or_jump)
xmap <C-k>     <Plug>(neosnippet_expand_target)

" SuperTab like snippets behavior.
" Note: It must be "imap" and "smap".  It uses <Plug> mappings.
"imap <expr><TAB>
" \ pumvisible() ? "\<C-n>" :
" \ neosnippet#expandable_or_jumpable() ?
" \    "\<Plug>(neosnippet_expand_or_jump)" : "\<TAB>"
smap <expr><TAB> neosnippet#expandable_or_jumpable() ?
\ "\<Plug>(neosnippet_expand_or_jump)" : "\<TAB>"

" For conceal markers.
if has('conceal')
  set conceallevel=2 concealcursor=niv
endif
" Enable snipMate compatibility feature.
let g:neosnippet#enable_snipmate_compatibility = 1

" Tell Neosnippet about the other snippets
let g:neosnippet#snippets_directory='~/.vim/bundle/snippets'

" to enable the section below, the following command required:
"
" $ pip3 install --user pynvim
" $ curl https://raw.githubusercontent.com/Shougo/dein.vim/master/bin/installer.sh > installer.sh
" $ sh ./installer.sh ~/.cache/dein
"
if &compatible
  set nocompatible
endif
" Add the dein installation directory into runtimepath
set runtimepath+=~/.cache/dein/repos/github.com/Shougo/dein.vim

if dein#load_state('~/.cache/dein')
  call dein#begin('~/.cache/dein')

  call dein#add('~/.cache/dein/repos/github.com/Shougo/dein.vim')
  call dein#add('Shougo/deoplete.nvim')
  if !has('nvim')
    call dein#add('roxma/nvim-yarp')
    call dein#add('roxma/vim-hug-neovim-rpc')
  endif

  call dein#end()
  call dein#save_state()
endif

filetype plugin indent on
syntax enable

let g:deoplete#enable_at_startup = 1

とりま、以下のシェルを実行する必要がありそうだ:

" $ pip3 install --user pynvim
" $ curl https://raw.githubusercontent.com/Shougo/dein.vim/master/bin/installer.sh > installer.sh
" $ sh ./installer.sh ~/.cache/dein

これで、~/.vim/snippets/[言語名].snip （python.snip/sh.snipとか）を編集すれば、

cat ~/.vim/snippets/
python.snip  rust.snip    sh.snip

各言語にそくしたスニペットをつくれる、例えば ~/.vim/snippets/python.snip にて、

snippet sample
        import sample

sample とうって (コントロール＋Kボタン)を押すと、 import sample を補完してくれる。
（注意: sampleと全部打つ必要あり）

snippet [エイリアス] の流れなので、これも注意

こんなかんじかな