nested_tree.ml

type 'a t =
  | Leaf of 'a
  | Node of (int -> 'a) t * (int -> 'a) t


let l = Leaf ();;

let f n = n
let g n k = n + k
let n = Node(Leaf f, Leaf f)

let n2= Node( Node(Leaf g, Leaf g), Leaf f)

let rec apply: 'a. 'a t -> ('a -> int) -> int =
  fun t k -> match t with
  | Leaf m -> k m
  | Node(l, r) ->
      apply l (fun f -> k (f 0)) + apply r (fun f -> k (f 1) )