LSP (language server protocol) integration

[gnestor]

Here we can discuss the future plans for LSP integration 👍

WIP PR: #12

[juliandolby]

Since JupyterCon is coming to New York soon, which is where I am, we had had thoughts of doing work on the hacking day after the conference. It could be a good opportunity for us to get together to push this integration, perhaps using pr #12 as a basis.

[ellisonbg]

I think this is a good first step (to plan on having folks gather to work on this at the JupyterCon Sprints). Pasting some general notes from elsewhere:

A few thoughts about LSP integration:

• We probably want to have a jupyter notebook server extension that can act as a proxy between specific LSPs and the frontend, through a standard web socket protocol and URLs. I am thinking of new endpoints like /lsp/python or /lsp/R and something that can return the list of available and running LSP servers.
• A new set of classes on jupyterlab services that has a well designed client to those endpoints and which returns the actual client LSP objects that Monaco needs.

[gnestor]

These two projects both offer monaco editors in JupyterLab with LSP support:

https://github.com/theia-ide/theia
https://github.com/R-Brain/jupyterlab

[gnestor]

I have created a PR to the enhancement-proposals repo regarding LSP support in jupyterlab-monaco: jupyter/enhancement-proposals#26