(* This code extends 'mini_prelude'. *)

datatype ('a) tree = 
    Tree of ('a) tree * 'a * ('a) tree 
  | Empty ;

val empty = Empty ;

fun member v4 = 
  (fn v5 => 
    (fn v6 => 
      (case v6 of 
          Empty => false 
        | (Tree (v3, v2, v1)) => 
            (if ((v4 v5) v2) 
            then (((member v4) v5) v3) 
            else 
              (if ((v4 v2) v5) 
              then (((member v4) v5) v1) 
              else true))))) ;

fun insert v4 = 
  (fn v5 => 
    (fn v6 => 
      (case v6 of 
          Empty => (Tree (Empty, v5, Empty)) 
        | (Tree (v3, v2, v1)) => 
            (if ((v4 v5) v2) 
            then (Tree ((((insert v4) v5) v3), v2, v1)) 
            else 
              (if ((v4 v2) v5) 
              then (Tree (v3, v2, (((insert v4) v5) v1))) 
              else (Tree (v3, v2, v1))))))) ;