struct Pack(Ts...)

{

    private Ts elements;

    // Access see my DIP; no alias this! Uses opStaticIndex.

    @property Ts[i] opStaticIndex(size_t i)() { return elements[i]; }

    enum length = elements.length;

    enum opDollar = elements.length;

​

    auto opDispatch(string memberName)()

    {

        return mixin((){

            string result = "pack[";

            static foreach (i; 0 .. elements.length)

            {

                result ~= mixin(`"elements[`,i,`].`, memberName, `,"`);

            }

            return result ~ "]";

        }());

    }

}

​

// makes pack[ x1, x2, x3 ] work and return a properly typed Pack.

struct pack

{

    static Pack!Ts opIndex(Ts...)(Ts args)

    {

        return Pack!Ts(args);

    }

}

​

struct S1

{

    int member;

    long other;

}

​

struct S2

{

    double member;

    string other;

}

​

unittest

{

    auto p = pack[ S1(1, long.max), S2(2.0, "twelve") ];

    auto q = p.member;

    static assert(is(typeof(q) == Pack!(int, double)));

    static assert(is(typeof(q.opStaticIndex!0) == int));

    static assert(is(typeof(q.opStaticIndex!1) == double));

    assert(q.opStaticIndex!0 == 1);

    assert(q.opStaticIndex!1 == 2.0);

}