gistfile1.ml

type 'a stream = Cons of 'a * (unit -> 'a stream)
let rec upfrom n = Cons(n, fun () -> upfrom(n+1))
let t = upfrom 0
let rec take n (Cons(x,xsf)) = if n=0 then [] else x::(take (n-1) (xsf()))

(*Here's the map function, the rest is just to set it up or demonstrate it*)
let rec map f (Cons(x,xsf)) = Cons( (f x), fun() -> map f (xsf()))

take 10 (map (fun x -> x+x) t);;