sbt server with Neovim

This is part 3 of sbt server integration series. I've covered VS Code and Sublime Text 3 thus far.

setting up neovim with sbt server

First, you need Python 3 and Node installed on your machine. Then update Neovim client library.

$ sudo pip3 install --upgrade neovim

Next, add eed3si9n/LanguageClient-neovim plugin to Neovim (or Vim) using your plugin manager. This is a fork of autozimu/LanguageClient-neovim repo so we can use the old Python based "master" branch since I couldn't get the latest "next" brach version to work.

Using Dein it looks like:

[[plugins]]
repo = 'eed3si9n/LanguageClient-neovim'

and you restart Neovim, :UpdateRemotePlugins. If it goes well, you should see:

remote/host: python3 host registered plugins ['LanguageClient']
remote/host: generated rplugin manifest: /Users/someone/.local/share/nvim/rplugin.vim
Press ENTER or type command to continue

Next, download sbt-server-stdio.js and save it to ~/bin/ or somewhere you keep scripts. sbt server by default uses Unix domain sockets on POSIX systems and named pipe on Windows, but editors seem to expect stdio. The script is a Node script that's included as our VS Code extension that discovers the socket, and fronts it with stdio.

We can now configure the Language Server client. In some configuration script:

set signcolumn=yes
 
let g:LanguageClient_autoStart = 1
 
let g:LanguageClient_serverCommands = {
    \ 'scala': ['node', expand('~/bin/sbt-server-stdio.js')]
    \ }
 
nnoremap <silent> gd :call LanguageClient_textDocument_definition()<CR>

usage

Run some project using sbt 1.1.0-RC2 or above. (Note RC-2, not RC-1 here).

Once the server comes up, open the directory using Neovim.

Similar to the VS Code extension, this integration is able to

• Run compile at the root project on saving *.scala files.
• Display compiler errors.
• Display log messages on :messages
• Jump to class definitons