lmao what. how. like what course of events....
I had several years professional experience, including functional programming, and still found it pretty rough going for a while. And even other professionals have often not even heard of it.
What there is is usually for a specific course, or is published by like Jane Street or some shit and highly domain-specific as well. I just found it hard to dig myself out when I ran into trouble.
I definitely agree about the FP concepts being no more difficult or even simpler to learn. I used to teach introductory programming to adults and at first we taught loops then map/filter etc and told students to use their preference.
Almost universally they used map, including complete synthesis of the entire concept of iteration without loops. Like when presented with a loop, I once saw a student skim the internal logic, see that it was doing an array push inside an if, and call it "a filter loop." To him the filter was the concept and the loop the tool, which is I think backwards from a lot of us.
Interestingly, it was the students with previous programming experience who had the most difficulties learning the language. I have not found the reverse to be true, the Ocaml compiler is very strict, but it makes you attentive to details and types in a way that transfers well to other languages.
The class hated it/him. Type errors were nothing short of terrifying. `function has type (a->(b->c)->(b->d)) but should have type (a->b->(c->b)->d)` or such. If you passed the class (a big if), you'd move on to C++ and OOP and never see Ocaml/functional again.
I appreciated it for providing me so much understanding wrt mathematical thinking - functional programming, recursion, induction. Later on I took some classes/researching using SML.
Fast-forward ~12 years and I get into web dev and what I see functional programming trending!? Kinda funny... I want to get into it somehow, probably Clojure this time. It just resonates with my thinking - maybe a product of being primed for it all those years ago.