OP strikes me as someone who is trying to position himself as a "moderate" but who is mistaking a caricaturized extreme (<0.25%) for "functional programmers". Honestly, I like FP extremists better than their OOP cargo-cult counterparts, who have the same smugness but are usually better, in most companies, at getting managerial blessing. In many companies, OOP acolytes glow in the managerial sun like Dudley Dursley, despite the general crappitude of their ideas.
"Functional programming" in the real world isn't about dogmatically eliminating mutable state. It's about managing it. It's about modularity. It's not far from the original vision behind OOP-- before it got taken away by the wrong crowd-- which was that when complexity is inevitable, it should be encapsulated behind simpler interfaces. For example, SQL is append-only (as functional as one can get over a growing knowledge base) if you never use DELETE or UPDATE. The inner guts of SQL are not "purely functional"-- caching and indexing cause internal state changes, for performance reasons-- but the interface is.
I don't even know what endofunctors are. If it's relevant to my job, I'll learn about them, but I care more about writing good software than reciting category-theory arcana. I'm sure it's important (especially as an inspiration for design) for some people, but you don't need to know them to do functional programming. Not even close. And I was already a productive functional programmer (in Ocaml and Lisp) before I even knew what monads were.
"Functional programming" in the real world isn't about dogmatically eliminating mutable state. It's about managing it. It's about modularity. It's not far from the original vision behind OOP-- before it got taken away by the wrong crowd-- which was that when complexity is inevitable, it should be encapsulated behind simpler interfaces. For example, SQL is append-only (as functional as one can get over a growing knowledge base) if you never use DELETE or UPDATE. The inner guts of SQL are not "purely functional"-- caching and indexing cause internal state changes, for performance reasons-- but the interface is.
I don't even know what endofunctors are. If it's relevant to my job, I'll learn about them, but I care more about writing good software than reciting category-theory arcana. I'm sure it's important (especially as an inspiration for design) for some people, but you don't need to know them to do functional programming. Not even close. And I was already a productive functional programmer (in Ocaml and Lisp) before I even knew what monads were.