I know, but you also said "but I'm pretty sure all the ones that exist" so I wanted to show you a counter-example. I'm also not surprised by your thought, since

I know, but you also said "but I'm pretty sure all the ones that exist" so I wanted to show you a counter-example. I'm also not surprised by your thought, since you are right - most of the time it gets mixed, which is actually sad. We need more practical pure functional programming libraries that focus on tackling problems with concurrent updates, streaming, state-changes etc. without forcing you to take a course in category theory beforehand.