Demonstration of ref patterns for avoiding moving out of &

gistfile1.txt

enum List<T> {
  End,
  Node { val: T, next: ~List<T> },
}
 
fn print_list<T:ToStr>(list: List<T>) {
  match list {
    End => { println("<X>"); },
    Node{val, next} => {
      println(val.to_str());
      print_list(*next);
    },
  }
}

// Need to take references to the fields so they
// don't get moved.
fn print_list2<T:ToStr>(list: &List<T>) {
  match *list {
    End => { println("<X>"); },
    Node{val: ref val, next: ref next} => {
      println(val.to_str());
      print_list2(*next);
    },
  }
}
 
fn main() {
  let list = ~Node{ val: 0, next:~Node{ val: 1, next:~End } };
  print_list2(list);
  print_list(*list);
}