"Functor" in Haskell has a very different meaning from "functor" in C++. In Haskell, a functor (loosely speaking) is any type you can map a function over--lists

"Functor" in Haskell has a very different meaning from "functor" in C++. In Haskell, a functor (loosely speaking) is any type you can map a function over--lists, trees, options, functions... If you squint, they're similar (but simpler and more general) to types that can be iterated over.