[klibertp]

> it is debatable whether OOP is a "good" style to develop at all!

You've drank way too much Kool-Aid here.

First of all: there are many different styles of OO, some more cumbersome than others, some so far removed from "classic OOP principles" that it takes effort to see how are they related. It's utterly useless to talk about "OOP style" as if it was a well defined, canonical set of rules - because it's not.

Second: there's nothing that makes OOP and FP be in opposition to each other. You should be aware - and if you're not, you should feel ashamed - that closures, one of basic FP tools, were supported in Smalltalk 20 years before Haskell.

Third: just as with OOP, things coming from FP are not uniformly "better" in any sense. Just as with every other paradigm, FP languages frequently have features needed only because they are FP. It makes very little sense to adopt those. Many really interesting features meant for solving real problems (and not for solving problems with a paradigm) are steadily coming to non-FP languages anyway.

> If I look at most of the libraries commonly used in production JS, pretty much none of them apply classic OOP principles.

Once again: either you have no idea what OOP is or you have no idea how JS libraries look like. For every http://ramdajs.com/docs/ you get hundreds libraries which implement their own kind of OO, starting from jQuery and Backbone.

[tel]

To be clear, "closures" are merely an implementation of lamdbas which were invented in the 30s. I wouldn't mention it except you're trying to shame someone for not "knowing" that Smalltalk beat Haskell to the punch despite both of them borrowing from a much richer history.

To drive the point home, you can implement lamdbas (and thus Haskell) without using closures. In fact, this is easy in a pure language since bindings are static. One way to do this is to compile the language into a basis of combinators like SKI. These no longer have any notion of binding so we don't need closures. Likewise, you could compile it into a categorical semantics and maybe implement this on FPGAs—again, no need for closures.

Lamdbas are merely a syntax and theory. Closures are merely one interpretation given a Von Neumann machine.

[klibertp]

I happen to know all this; what I wanted to stress is not the nature of closures, which is exactly as you say, but that they were used since long ago in a "purely object oriented" languages, which - AFAIK - are not meant to implement lambda calculus in any shape or form.

GP wrote that - in short "everything in OOP is bad, let's use FP only". I responded with an argument that, in fact, certain OOP languages used FP features long before Haskell (because that's the example GP provided). I don't think the fact that closures are just one interpretation of an abstract concept of "lambda" is very relevant to this argument.

And about "shaming" people: I meant to gently point out that advocates for some cause should at the very least get their facts straight. Bashing some concept without knowing it well is the thing I objected to, a "not knowing it well" part by itself wouldn't be anything one should feel ashamed of.

[tel]

I suppose I read it overly antagonistically then. Honestly, the entire FP/OO thing is so draining. I wish we'd all just start talking about Church/Curry debates instead. It's dispense with most of the marketing mumbo jumbo.