LSP Server for Scheme (and more ...)

[r . herdt]

Hi Guilers!

I want to share a couple of things I have being working on that you may 
find useful.

1) I developed an LSP Server for Scheme. For those that don't know the 
Language Server Protocol (LSP), it is meant for adding programming 
language support for IDEs and editors that implement the protocol 
(nowadays most of them support it).

For now I am focusing on Guile 3 and CHICKEN 5. The idea is to write as 
much R7RS for common code as possible (like representing documents, 
fetching word under cursor etc.) and leave implementation specific code 
to dedicated files. So far I managed to implement auto-completion, fetch 
signature, fetch documentation and jump to definition.

Repo: https://codeberg.org/rgherdt/scheme-lsp-server

2) An LSP server without a client is quite useless, so I'm also sharing 
an emacs-lsp client:

Repo: https://codeberg.org/rgherdt/emacs-lsp-scheme

I will create a PR to melpa for this. Until it is merged, you can clone 
the repo somewhere, 'load' it and follow the instructions in the README 
to activate it.

Usage is based on interaction with the REPL, which is based on Emacs's 
built-in scheme inferior-mode. So you have to load the file (say by 
typing C-c C-l on a buffer) in order to get access to symbols imported 
from other modules.

Note: for daily use you probably should stick to Geiser, since its Guile 
support is obviously much more mature. It can still become useful for 
other Schemes though, and is a good way to develop the LSP server 
without leaving Emacs ;)

3) The whole idea behind LSP is to improve language support across 
multiple IDEs/editors. So I started a proof of concept in VS Code:

https://codeberg.org/rgherdt/vscode-scheme-lsp

Since I don't use VS Code, I don't expect spending much time on it. I 
also don't know how a lispy LSP client should/could look like in VS 
Code. If you have ideas, or want to contribute/take over this, feel free 
to contact me. It is not documented nor published yet, but already works 
for the functionality mentioned (there are a couple of command to launch 
a REPL and load files on it). I will investigate how to automate 
installation of the LSP server before publishing it and let you know.

Everything is on an early stage of development, and APIs may change. I 
tested it using following software:
- Guile 3.0.8
- Emacs 27.1 and 28.1
- Debian Bullseye and Ubuntu 18.04

Any questions, suggestions, critics and contributions are more than 
welcome. We can also reach me on @libera's #guile, #chicken, #scheme 
channels by the name rgherdt.

Have a nice weekend you all!

Ricardo