Linked List push function

list_push_fn

#[deriving(ToStr, Clone, Eq)]
enum List<T> {
    Cons(T, @mut List<T>),
    Nil
}

/* 
 * from brson: it could be more efficient by avoiding that clone,
 * since the cost of cloning a T could be arbitrary.
 *
 * with that signature, one thing you could do is swap Nil into l,
 * then assign the new Cons to l without cloning the original l
 *
 * from bdaupp: it's hard to avoid both the infinite loop and the .clone with
 * that design (i.e using @mut), personally I'd take either &mut @mut List, or
 * return a new @mut List with the body being @mut Cons(v, l)
 *
 */


pub fn push<T: 'static + Clone>(l: &mut List<T>, v: T) {
    *l = Cons(v, @mut((*l).clone()));
}

/*
pub fn pop<T: Clone>(l: &mut List<T>) -> T {
    *l = 
}
*/

fn main() {
    let list = @mut Cons(1i, @mut Nil);
    push(list, 2i);
    push(list, 3i);

    println(list.to_str());
}