structure M = struct datatype t = A | B end val f = fn x : M.t => case x of M.A => M.B | M.B => M.A datatype t = datatype M.t val g = fn x : t => case x of M.A => B | B => M.A structure N = struct datatype u = C of t | D end val h = fn x : N.u => case x of N.C x => x | N.D => M.A datatype u = datatype N.u val i = fn x : u => case x of N.C x => x | D => M.A val toString = fn x => case x of C A => "C A" | C B => "C B" | D => "D" val rec page = fn x => return {cdata (toString x)}

Again!
val main : unit -> transaction page = fn () => return
  • C A
  • C B
  • D