[jjice]

University (like a lot of CS students I'd assume). I always saw it as an academic thing and didn't give it much use until my compiler course. My professor for the course maintains a somewhat well known SML compiler and our course was writing a very formal functional programming language in SML. A lot of the power starting falling into place at that point. ADTs especially were eye opening.

I don't write in pure FP languages now, but I do use the concepts I learned all the time, especially as their fantastic concepts are leaking into other languages, like Rust.

I don't think pure FP languages will ever be real industry winners, but I think they're great experiment and research grounds for features that the broader community eventually adopts, which is such an important thing for improving the expressibility of our code.