I remember, about a week into my exposure to Ocaml, asking what a functor was. "It's a function from a module to a module." My response was along the lines of,

I remember, about a week into my exposure to Ocaml, asking what a functor was. "It's a function from a module to a module." My response was along the lines of, What? It turns out, though, that Ocaml functors are really cool and can provide some of the functionality of Haskell's type classes.