This is my attempt on writing a remote plugin framework without :UpdateRemotePlugins.

• has('python3')
• For Vim 8:
  • roxma/vim-hug-neovim-rpc
  • g:python3_host_prog pointed to your python3 executable, or echo exepath('python3') is not empty.
  • pynvim (pip3 install pynvim)

    " Required for vim 8
    Plug 'roxma/vim-hug-neovim-rpc'
    " Install this plugin
    Plug 'roxma/nvim-yarp', { 'do': 'pip install -r requirements.txt' }

• shougo/deoplete.nvim
• ncm2/ncm2 and most of its plugins

pythonx/hello.py

import vim, time
def greet():
    time.sleep(3)
    vim.command('echo "Hello world"')

plugin/hello.vim

" Create a python3 process running the hello module. The process is lazy load.
let s:hello = yarp#py3('hello')

com HelloSync call s:hello.request('greet')
com HelloAsync call s:hello.notify('greet')

" You could type :Hello greet
com -nargs=1 Hello call s:hello.request(<f-args>)

Add logging settigns to your vimrc. Log files will be generated with prefix /tmp/nvim_log. An alternative is to export environment variables before starting vim/nvim.

let $NVIM_PYTHON_LOG_FILE="/tmp/nvim_log"
let $NVIM_PYTHON_LOG_LEVEL="DEBUG"

let s:yarp.on_load = function('your_handler')

A handler that is called after your python module is loaded. It is not considered ready for request or notification from vimscript during loading stage. s:yarp.request and s:yarp.notify internally wait until on_load before sending actual request and notification.

call s:yarp.reqeust({event}, [, {args}...])

Similiar to :help rpcrequest. It sends a request to the rpc channel and returns the result of your python method.

call s:yarp.rpcnotify({event}, [, {args}...])

Similiar to :help rpcnotify. It sends a notification to the rpc channel and returns immediately.

call s:yarp.error(msg)

Print error message.

call s:yarp.warn(msg)

Print warning message.

More realistic examples could be found at nvim-typescript#84, deoplete#553, callmekohei/quickdebug.

Now let's consider the following simple rplugin.

After UpdateRemotePlugins and restarting neovim, you get foobar by :echo Bar().

# rplugin/python3/foo.py
import pynvim

@pynvim.plugin
class Foo(object):

    def __init__(self, vim):
        self._vim = vim

    @pynvim.function("Bar", sync=True)
    def bar(self, args):
        return 'hello' + str(args)

For working on Vim 8, you need to add these two files:

" plugin/foo.vim
if has('nvim')
    finish
endif

let s:foo = yarp#py3('foo_wrap')

func! Bar(v)
    return s:foo.call('bar',a:v)
endfunc

# pythonx/foo_wrap.py
from foo import Foo as _Foo
import vim

_obj = _Foo(vim)


def bar(*args):
    return _obj.bar(args)

How to use

$ vim

: echo bar('world')

hello('world',)