struct list {
  value: string;
  next: list|void;
}

fun empty() {
  return null as list|void
}

fun cons(v: string, l: list|void) {
  make list(value:v, next:l) as list|void
}

main = fun() {
  l = cons("first", cons("second", cons("third", empty())));

  h = l;
  next = empty();

  /*
   * Note that we cannot say "h = h.next" in the following loop,
   * as inside the typecase, h has a different type from h.next.
   * So we do the next best thing.  (Pun not intended.)
   */
  while true {
    typecase h is void { break; }
    typecase h is list {
      print(h.value);
      next = h.next;
    }
    h = next;
  }
}