LSP Server for CHICKEN (and more ...)

[Ricardo G. Herdt]

Hi folks!

I mentioned my work on an LSP server for Scheme a while ago. 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). After a long pause 
period due to private reasons, I finally managed to get it into a 
working state, so here my results:

1) You can find the server here:
https://codeberg.org/rgherdt/scheme-lsp-server

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. "Jump to 
definition" has some particularities in the CHICKEN case (I basically 
scan some paths for scheme files and keep track of changes) see 
https://codeberg.org/rgherdt/emacs-lsp-scheme#chicken.

note: salmonella's Testing is failing, although chicken-install -test 
works. I'm investigating it.

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.

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 know how similar extensions typically 
work and don't have a clear idea how a lispy LSP client should/could 
look like in it. If you have ideas, or want to contribute, feel free to 
contact me. It is not documented nor published yet, but already works 
for the functionality mentioned (there are a couple of commands 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:
- CHICKEN 5.3.0
- Guile 3.0.8
- Emacs 27.1 and 28.1
- Debian Bullseye and Ubuntu 18.04

Any questions, suggestions, critics and contributions are welcome. You 
can also reach me on @libera's #chicken, #scheme channels (rgherdt).

Have a nice weekend!

Ricardo