The actual 0install Python code does use optparse. It wasn't stated in the post, but the next step after writing this code was to use it as a front-end to the

The actual 0install Python code does use optparse. It wasn't stated in the post, but the next step after writing this code was to use it as a front-end to the real Python version. If invoked as "0install run NAME ARGS..." exactly then we handle it (the fast path), otherwise we fall back to the Python version. In particular, that means that the Haskell/OCaml version must NOT try to handle --help, etc. I wrote the comparison Python code to be similar to the other languages. This OCaml front-end appeared in 0install 2.3. For 0install 2.4 there is a full option parser written in OCaml. I didn't use a library for this because a) it needs to be 100% compatible with the Python parsing and b) it needs to handle tab-completion too.