I recently finished a basic XLSX reader for OCaml and I thought it would be a good time to summarize what's necessary to make a library like this, since the documentation is complicated and sometimes hard to find.
If you're planning to read XLSX files, you probably want to …
From a non-theoretical engineer perspective, a monad is a kind of container that you can apply functions to to get a new monad. In particular, you need a way to put something into your monad and a way to apply changes to it. These are called return and bind. There is also a third operation, map, which is a combination of the two. Note that monads are allowed to be empty, which will make bind and map not do anything; and they can also contain more than one thing (in which case bind and map will call the function you give them more than once and merge the results).
The main difference between the two formats is that in ZIP, compression is built-in and happens independently for every file in the archive, but for tar, compression is an extra step that compresses the entire archive. This means ZIP has better random access while tar+compression will generally provide better compression.
One of the hardest parts of learning OCaml is figuring out what the infix operators do, since they're just a string of symbols and you can't find them with a Google search. This is my attempt to make a cheatsheet for whenever you're wondering what a random series of symbols means.
I've been keeping a computer setup page on my website for a while, describing the exact steps needed to make a computer work how I want after a new OS install. I've also had a note there for years saying eventually I should use Ansible for this. This weekend I finally got around to it, and learned a little bit about Ansible while I was at it.