I have written a small utility class to provide "empty member optimization" for arbitrary types. The implementation makes use of the empty base class optimization (EBCO) but avoids injection of the class. A uniform and contained interface is exposed wether the optimization applies or not:
I believe this could be used as the basis for a compressed_tuple.
Here's a sample use:
template <typename T0, typename T1> struct A : private compressed_member<T0> , private compressed_member<T1, 1> { typedef compressed_member<T0> member0; typedef compressed_member<T1, 1> member1;
T0 const & first() { return base0::get(); } T1 const & second() { return base1::get(); } };
How does this differ from boost::compressed_pair ? John.