Double link list

[Joel]

I'm trying some code for practice, but it isn't working properly 
- it prints just one number when printing in reverse.

'''
void main() {
	import std.stdio, std.algorithm, std.range, std.conv;
	struct List(T) {
		class Node {
			T value;
			Node next, prev;
			this(T value0) {
				value = value0;
			}
		}
		Node head, tail;
		auto opOpAssign(string op)(T value) if (op == "~") {
			auto newNode = new Node(value);
			if (head is null) {
				head = tail = newNode;
			} else {
				tail.next = newNode;
				tail.next.prev = tail;
				tail = tail.next;
			}
			return this;
		}
		auto opOpAssign(string op)(T[] values) if (op == "~") {
			values.each!(v => this ~= v);
			return this;
		}
		@property {
			bool empty() { return head is null || tail is null; }
			ref auto front() { return head.value; }
			ref auto back() { return tail.value; }			
		}
		void popFront() { head = head.next;  if (head !is null) 
head.prev = null; }
		void popBack() { tail = tail.prev; if (tail !is null) tail.next 
= null; }
		auto save() { return this; }
	}
	auto ints = List!int();
	ints ~= [0,1,2,3,4];
	ints = ints.dropOne;
	writeln(ints);
	writeln(ints.retro); // just prints 4
}
'''