ncm, I don't think you understand, what I have done is not to implement Ocaml in Ocaml, I have expressed a simple recursive function which happens to be a library function.

Ocaml includes "map" as a function expressed in Ocaml, here is how they define it:

let rec map f = function
    [] -> []
  | a::l -> let r = f a in r :: map f l

I not quite sure why they do it this way, I think they use pattern matching because of the the builtin error reporting, let r = f a in r :: map f l could be expressed: f a :: map f l .