I’m working on a programming language[1] that started as an excuse to read PLT papers and build a syntax I could easily read to help explore some ideas. I ended up building a functional language with a capability system that doesn’t require you to thread capabilities through every call with an effect. I also ended up building a package manager, cargo like tool, hoogle like code search, and a slew of other features. I’ve mainly been running the development process through Claude because I’m more interested in learning about the higher level concepts than the particulars of turning code into an LLVM IR.
It’s usable today but the capability features are not ready in the last numbered release, just main or nightly. You can also try it in the site via js_of_ocaml[2]. The docs are a little rough, I plan to hand rewrite them soon.