Totally agree that these paradigms are badly defined. See my other comment where I explain it more https://news.ycombinator.com/item?id=34217547

My point here was that all "OOP" languages (that I know) allow you, with all their "OOP feautres", to work with objects which actually don't contain any mutable state.

I'll let you be the judge whether it is still "OOP", but I know from experience that it's very practical for Software Engineering.