LSP support

[bruno-medeiros]

@jonathandturner I was pointed to the lsp_support branch by @nrc , and I was wondering how far/mature that work is? I've been working on LSP implementation for Rust (https://github.com/RustDT/RustLSP), and I was wondering if this could be of use for RustLS? (RustLSP is meant to be independent of the actual language the server engine is made for)

RustLSP is still in early stages too, but I'm planning to make it more complete and robust.

[sophiajt]

We're hoping to finish standing it up this week. Currently, there are a few remaining bugs, but after those are fixed, the support should look something like:

• Completion
• Find all refs
• Goto symbol
• Goto def
• Type on hover

Hmm, I'm probably forgetting 1 or 2, but that's the gist. It's meant to mirror what the RLS can do.

[sophiajt]

...all that said, if you're interested in helping, once all the major bugs are fixed we're planning on doing a source release and opening it up to contributors. We've just been in the phase of "get it working" so far :)

[bruno-medeiros]

I am indeed interested in contributing, but for now at least just on the LSP side of things (the server protocol, not the engine). I'll leave the engine work for you guys :)
But yeah, I wanna get RustLSP ready for use, and flesh it out. Basically:

• test it and fix some pending bugs.
• add support for concurrent JSON-RPC request processing.
• properly separate client from server interface.
• address some protocol ambiguities (see Simplify protocol with regards to optional fields vs nullable fields. microsoft/language-server-protocol#87 )

Once I get it working properly such that it can serve a dummy/fake language for at least the core functionality, it should be trivial to hook it up to RLS, especially since you already have some code in the lsp_branch exemplifying how to do that for the common LSP requests.

[bruno-medeiros]

So I've done that and adapted rls to use RustLSP : https://github.com/bruno-medeiros/rls/tree/rustlsp

Just need to do some more testing and I'll prep a PR

[nrc]

We're now using LSP as our only protocol. Closing.