The are LLVM Caleidoscope (toy compiler) in both Haskell and OCaml

https://github.com/sdiehl/kaleidoscope https://github.com/arbipher/llvm-ocaml-tutorial

The Haskell one is a nice one. Can say nothing about the OCaml one since I found it using a google search.

I've had a try at implementing an Caleidoscope compiler in OCaml but did not finish it. But it was fun to write.