Use Ocaml Language.

Implement the function inorder : a tree -> a list that lists the nodes of a tree in the order given by an in-order traversal. (So, inorder applied to the above tree would give [4;2;5;1;3].) Use tree_fold. Do not use recursion.

The base code:

(** Trees **)

type 'a tree = Leaf | Node of 'a * 'a tree * 'a tree ;;

let rec tree_fold (t: 'a tree) (u: 'b) (f: 'a -> 'b -> 'b -> 'b) = match t with | Leaf -> u | Node (v, l, r) -> f v (tree_fold l u f) (tree_fold r u f)

let inorder (t: 'a tree) : 'a list = raise ImplementMe