(* Written by Stephen Weeks (sweeks@sweeks.com). *)
fun merge (l1: int list, l2) =
   case (l1, l2) of
      ([], _) => l2
    | (_, []) => l1
    | (x1 :: l1', x2 :: l2') =>
         if x1 <= x2
            then x1 :: merge (l1', l2)
         else x2 :: merge (l1, l2')
      
structure Main =
   struct
      fun doit size =
         let
            val len = 100000
            val l1 = List.tabulate (len, fn i => i * 2)
            val l2 = List.tabulate (len, fn i => i * 2 + 1)

            fun test () =
               if 0 = hd (merge (l1, l2))
                  then ()
               else raise Fail "bug"

            fun loop n =
               if n = 0
                  then ()
               else (test (); loop (n - 1))
         in
            loop size
         end
   end