[quickthrower2]

And also what is an 'object'?

Haskell has a decent system for building up complex data structures. You can write functions for those. Those data structures + those functions are kind of "an object" from the OO world (data + methods).

The differences are:

* Inheritance - well Haskell has many kinds of polymorphism so it doesn't need it.

* Hiding data - well Haskell can hide data using smart constructors, you don't need an explicit private keyword

* Interfaces - covered by typeclasses but they do a lot more!

Also without any of the above you can create object-like things with just closures. If a scope has access to 3 variables in scope, it's "kinda" like an OO object with 3 member variables. You can create new scopes in a for loop, which is like creating many new object. It's a stretch but the underlying concept of something owning other things is still there.

[ufo]

> Those data structures + those functions are kind of "an object"

And in this setting, the type of that datastructure containing the functions can act as an interface.

A trap that OO programmers sometimes fall into with Haskell is to try to emulate OO interfaces using existential types + typeclass interfaces but that is a bit of an antipattern.