After I finished the MOOC on OCaml recently, I really wanted to use it in a real world scenario (as opposed to the web-based editor in the course). As it happens, I also required a command-line tool for disentangling log messages, so I went ahead and wrote it in Python first and reimplemented it in OCaml afterwards. It’s on GitHub. The python implementation took me about 1 hour (including tests and so forth) and was mainly to figure out what the software should do.
Main takeaway: OCaml is awesome, and the tools are as well. However, I spent most time on this project on getting oasis to run as I want it to (and I’m still not convinced that I have set everything up correctly). But seeing the man page created by Cmdliner is just worth all the trouble!