Of course, having heard of the concept already, we'd all like to fancy ourselves smart enough to …

That might be, probably is. But the representation of FP gets mostly done by those who are only halfway there, creating an impression that it is a better way of programming overall, when it’s just a mixed bag of approaches dictated by a set of esoteric languages (from business pov). The worst part is that it doesn’t translate verbatim to any non-fringe language and creates a mess in it, due to adopted inertia. At least that is my experience with FP “recruitment”. I wish I skipped this FP tour completely and instead learned how to structure my programs directly. Could save me a year or five. Maybe there’s no better way, but in practice clear explanations are always better than these arcane teachings where you repeat something until you get it by yourself.

"In theory, you could pick up your one language, say, Java, and through the course of a normal career learn everything necessary to program in that language in the best possible way." OK, then you know about currying, immutable data structures, map/reduce/filter, &c. Because Java has that since way back when. No real closures, I think, but that doesn't matter much because the anonymous functions do what you want pretty much all the time and you could probably invent your own closures if you really want something else.

> FP has more to say about purity of functions, the utility of composition of small parts, the flexibility of composition with small parts, ways to wrap parts of the program that can't be handled that way, and providing an existence proof that despite what an imperative programmer might think it is in fact possible to program this way at a system architecture level. Adding to that, in my case it also made realize that deterministic elimination of entire classes of errors in large, complex code bases, in a systematic rather than ad-hoc way, is actually possible. Prior to discovering fp, and particularly Haskell's type system, I spent much effort trying to do that with a combination of TDD and increasingly elaborate try/catch/throw error handling. Discovering Haskell's compiler, type system, and monadic quarantining of effects obsoleted all that effort and was a huge eye opener for me. An…