Introduction

NCM2, formerly known as nvim-completion-manager, is a slim, fast and hackable completion framework for neovim.

Main features:

1. Fast and asynchronous completion support, with vimscript friendly API.
2. Smart on files with different languages, for example, css/javascript completion in html style/script tag.
3. Function parameter expansion support using ncm2-snippet plugins.
4. Language server protocol plugin integration.

Read our wiki page for a list of extensions and programming languages support for NCM2.

View demo vimrc at #19

Requirements

• :echo has("nvim-0.2.2")

  prints 1. Older versions has not been tested

• :echo has("python3")

  prints 1. This is usually set by

  python3 -m pip install pynvim

  in shell and

  let g:python3_host_prog=/path/to/python/executable/

  in vimrc.
• Plugin nvim-yarp

For vim8 user, read the nvim-yarp README. Note that vim8 support is simply a bonus. It's not the goal of NCM2.

Install

    " assuming you're using vim-plug: https://github.com/junegunn/vim-plug
    Plug 'ncm2/ncm2'
    Plug 'roxma/nvim-yarp'

" enable ncm2 for all buffers
autocmd BufEnter * call ncm2#enable_for_buffer()

" IMPORTANT: :help Ncm2PopupOpen for more information
set completeopt=noinsert,menuone,noselect

" NOTE: you need to install completion sources to get completions. Check
" our wiki page for a list of sources: https://github.com/ncm2/ncm2/wiki
Plug 'ncm2/ncm2-bufword'
Plug 'ncm2/ncm2-path'

Optional Vimrc Tips

    " suppress the annoying 'match x of y', 'The only match' and 'Pattern not
    " found' messages
    set shortmess+=c

" CTRL-C doesn't trigger the InsertLeave autocmd . map to <esc> instead.
inoremap <c-c> <esc>

" When the <enter> key is pressed while the popup menu is visible, it only
" hides the menu. Use this mapping to close the menu and also start a new
" line.
inoremap <expr> <cr> (pumvisible() ? "\<c-y>\<cr>" : "\<cr>")

" Use <tab> to select the popup menu:
inoremap <expr> <tab> pumvisible() ? "\<c-n>" : "\<tab>"
inoremap <expr> <s-tab> pumvisible() ? "\<c-p>" : "\<s-tab>"

" wrap existing omnifunc
" Note that omnifunc does not run in background and may probably block the
" editor. If you don't want to be blocked by omnifunc too often, you could
" add 180ms delay before the omni wrapper:
"  'on_complete': ['ncm2#on_complete#delay', 180,
"               \ 'ncm2#on_complete#omni', 'csscomplete#CompleteCSS'],
au User Ncm2Plugin call ncm2#register_source({
        \ 'name' : 'css',
        \ 'priority': 9,
        \ 'subscope_enable': 1,
        \ 'scope': ['css','scss'],
        \ 'mark': 'css',
        \ 'word_pattern': '[\w\-]+',
        \ 'complete_pattern': ':\s*',
        \ 'on_complete': ['ncm2#on_complete#omni', 'csscomplete#CompleteCSS'],
        \ })

How Do I write Ncm2 Source?

One important step is to understand how and when completion gets triggered. Read

:help ncm2#register_source

:help
ncm2#register_source-example

In case you don't know what tool you should use for async support. Here are some options available:

• :help jobstart()

• python remote plugin example
• I myself prefer to use nvim-yarp
  • Read ncm2/ncm2-bufword for example

Debugging

Refer to the debugging section of nvim-yarp