----- Original Message ----- From: "Robert Ramey" <ramey@rrsd.com> To: <boost@lists.boost.org> Sent: Sunday, February 14, 2010 11:28 PM Subject: Re: [boost] Downcast taking account of virtual inheritance
Kim Barrett wrote:
I think the correct fix is to leave the existing derivation test in place, but augment it with the is_virtual_base_of test, i.e. mpl::or_ the existing test for cross-cast (T and U have no base/derived relationship) with the is_virtual_base_of test.
That would sound correct to me.
I have teste this and this should complete conveniently the smart_cast function. typedef BOOST_DEDUCED_TYPENAME mpl::eval_if< BOOST_DEDUCED_TYPENAME mpl::or_< is_virtual_base_of<U, BOOST_DEDUCED_TYPENAME remove_pointer<T>::type, BOOST_DEDUCED_TYPENAME mpl::and_< mpl::not_<is_base_and_derived< BOOST_DEDUCED_TYPENAME remove_pointer<T>::type, U > >, mpl::not_<is_base_and_derived< U, BOOST_DEDUCED_TYPENAME remove_pointer<T>::type > > > >, // borland chokes w/o full qualification here mpl::identity<cross>, mpl::identity<linear> >::type typex; return typex::cast(u); Robert, could you add this enhancement for the next release. Thanks, Vicente