regression/circular.sml

   1 open Vector
   2
   3 datatype t = T of t vector
   4 fun makeT () = T (tabulate (0, fn _ => makeT ()))
   5 fun destT (T v) =
   6    if length v > 0
   7       then 1 + destT (sub (v, 0))
   8    else 0
   9 val _ =
  10    if 0 = destT (makeT ())
  11       then ()
  12    else raise Fail "bug"