template Singleton(T) {
    private static T _instance;
    private static bool _deleted = false;

    public static T get() {
        assert(!_deleted);

        if (_instance is null) {
            _instance = new T();
        }
        return _instance;
    }

    public static void destroy() {
        assert(!_deleted);
        delete _instance;
        _deleted = true;
        _instance = null;
    }
}

unittest {

    class Foo {
        mixin Singleton!(Foo);

        private this() {
            printf("Constructor!");
        }
    }

    Foo a = the!(Foo)();
    Foo b = the!(Foo)();

    assert(a is b);
}

// best global symbol name ever
template the(T) {
    T the() {
        return T.get();
    }
}