# vim-hug-neovim-rpc
This is an **experimental project**, trying to build a compatibility layer for
[neovim rpc client](https://github.com/neovim/python-client) working on vim8.
I started this project because I want to fix the [vim8
support](https://github.com/roxma/nvim-completion-manager/issues/14) issue for
[nvim-completion-manager](https://github.com/roxma/nvim-completion-manager).
Since this is a general purpose module, other plugins needing rpc support may
benefit from this project. However, there're many neovim rpc methods I haven't
implemented yet, which make this an experimental plugin. **Please fork and
open a PR if you get any idea on improving it**.
***Tip: for porting neovim rplugin to vim8, you might need
[roxma/nvim-yarp](https://github.com/roxma/nvim-yarp)***
## Requirements
1. vim8
2. If `has('pythonx')` and `set pyxversion=3`
- same requirements as `4. has('python3')`
2. Else if `has('pythonx')` and `set pyxversion=2`
- same requirements as `5. has('python')`
4. Else if `has('python3')`
- [pynvim](https://github.com/neovim/pynvim)
- Pynvim is normally installed by `:py3 import pip; pip.main(['install',
'--user', 'pynvim'])` or `python3 -m pip install pynvim`.
- There should be no error for at least one of `:python3 import pynvim` and
`:python3 import neovim`
5. Else if `has('python')`
- [pynvim](https://github.com/neovim/pynvim)
- Pynvim is normally installed by `:py import pip; pip.main(['install',
'--user', 'pynvim'])` or `python2 -m pip install pynvim`.
- There should be no error for at least one of `:python3 import pynvim` and
`:python3 import neovim`
6. `set encoding=utf-8` in your vimrc.
***Use `:echo neovim_rpc#serveraddr()` to test the installation***. It should print
something like `127.0.0.1:51359` or `/tmp/vmrUX9X/2`.
## API
| Function | Similar to neovim's |
|----------------------------------------------|------------------------------------------------|
| `neovim_rpc#serveraddr()` | `v:servername` |
| `neovim_rpc#jobstart(cmd,...)` | `jobstart({cmd}[, {opts}])` |
| `neovim_rpc#jobstop(jobid)` | `jobstop({job})` |
| `neovim_rpc#rpcnotify(channel,event,...)` | `rpcnotify({channel}, {event}[, {args}...])` |
| `neovim_rpc#rpcrequest(channel, event, ...)` | `rpcrequest({channel}, {method}[, {args}...])` |
Note that `neovim_rpc#jobstart` only support these options:
- `on_stdout`
- `on_stderr`
- `on_exit`
- `detach`
## Incompatibility issues
- Cannot pass `Funcref` object to python client. Pass function name instead.
- Python `None` will be converted to `''` instead of `v:null` into vimscript.
See [vim#2246](https://github.com/vim/vim/issues/2246)
- The following neovim-only API will be ignored quietly:
- `nvim_buf_add_highlight`
- `nvim_buf_clear_highlight`
## Overall Implementation
```
"vim-hug-neovim-rpc - Sequence Diagram"
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
┌───┐ ┌──────────┐ ┌───────────┐ ┌──────┐
│VIM│ │VIM Server│ │NVIM Server│ │Client│
└─┬─┘ └────┬─────┘ └─────┬─────┘ └──┬───┘
│ Launch thread │ │ │
│───────────────────> │ │
│ │ │ │
│ Launch thread │ │
│─────────────────────────────────────────────────>│ │
│ │ │ │
│ `ch_open` connect │ │ │
│───────────────────> │ │
│ │ │ │
│ │────┐ │ │
│ │ │ Launch VimHandler thread│ │
│ │<───┘ │ │
│ │ │ │
│ │ │ Connect │
│ │ │<─────────────────────────────
│ │ │ │
│ │ ────┐
│ │ │ Launch NvimHandler thread
│ │ <───┘
│ │ │ │
│ │ │ Request (msgpack rpc) │
│ │ │<─────────────────────────────
│ │ │ │
│ │ ────┐ │
│ │ │ Request enqueue │
│ │ <───┘ │
│ │ │ │
│ │ notify (method call) │ │
│ │ <────────────────────────────│ │
│ │ │ │
│ notify (json rpc) │ │ │
│<─────────────────── │ │
│ │ │ │
────┐ │ │
│ Request dequeue │ │
<───┘ │ │
│ │ │ │
────┐ │ │ │
│ Process │ │ │
<───┘ │ │ │
│ │ │ │
│ │ Send response (msgpack rpc) │
│────────────────────────────────────────────────────────────────────────────────>
┌─┴─┐ ┌────┴─────┐ ┌─────┴─────┐ ┌──┴───┐
│VIM│ │VIM Server│ │NVIM Server│ │Client│
└───┘ └──────────┘ └───────────┘ └──────┘
```
<!--
@startuml
title "vim-hug-neovim-rpc - Sequence Diagram"
VIM -> "VIM Server": Launch thread
VIM -> "NVIM Server": Launch thread
VIM -> "VIM Server": `ch_open` connect
"VIM Server" -> "VIM Server": Launch VimHandler thread
Client-> "NVIM Server": Connect
"NVIM Server" -> "NVIM Server": Launch NvimHandler thread
Client -> "NVIM Server": Request (msgpack rpc)
"NVIM Server" -> "NVIM Server": Request enqueue
"NVIM Server" -> "VIM Server": notify (method call)
"VIM Server" -> VIM: notify (json rpc)
VIM -> VIM: Request dequeue
VIM -> VIM: Process
VIM -> Client: Send response (msgpack rpc)
@enduml
-->
## Debugging
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.
```vim
let $NVIM_PYTHON_LOG_FILE="/tmp/nvim_log"
let $NVIM_PYTHON_LOG_LEVEL="DEBUG"
```