finalStm :: Stm -> PP Stm
finalStm s =
  case s of
    Assign _ _ s'   -> finalStm s'
    Case _ _ _ next -> finalStm next
    Forever s'      -> finalStm s'
    _               -> return s
finalStm :: Stm -> PP Stm
finalStm s =
  case s of
    Assign _ _ s'   -> finalStm s'
    Case _ _ _ next -> finalStm next
    Forever s'      -> finalStm s'
    _               -> return s
finalStm s =
  case s of
    Assign _ _ s'   -> finalStm s'
    Case _ _ _ next -> finalStm next
    Forever s'      -> finalStm s'
    _               -> return s