(* --- File Tree.ml ---
 * Time-stamp: <Thu Jan 18 10:42:58 2018 (mz)>
 * Created on: <Thu Jan 18 10:40:47 2018> by mz@labri.fr on [Espelette] *)

type 'a tree = Empty | Bin of 'a * 'a tree * 'a tree

let rec infix t f =
  match t with
  | Empty -> ()
  | Bin(v, l, r) -> infix l f; f v; infix r f

let rec prefix t f =
  match t with
  | Empty -> ()
  | Bin(v, l, r) -> f v; prefix l f; prefix r f

let rec postfix t f =
  match t with
  | Empty -> ()
  | Bin(v, l, r) -> postfix l f; postfix r f; f v

let leaf v = Bin(v, Empty, Empty)

let p = Bin(1, Bin(2, leaf(3), leaf(4)), Bin(5, leaf(6), leaf(7)))

let _ = prefix p (fun v -> Printf.printf "%d " v)
let _ = infix p (fun v -> Printf.printf "%d " v)
let _ = postfix p (fun v -> Printf.printf "%d " v)

(* tree.ml ends here *)