That's actually very useful! However a less complicated interface would definitely be more appreciated! Maybe some wrapper functions or macros would do the trick. Στις 5:16 μ.μ. Παρασκευή, 20 Μαρτίου 2015, ο/η Mathias Gaunard <mathias.gaunard@ens-lyon.org> έγραψε: On 20/03/2015 17:49, costis glynos wrote:
You also need to use Boost.Fusion to make it into a tuple at the end, since this is what you want.
Here is an example:
#include <boost/mpl/sort.hpp> #include <boost/mpl/vector.hpp> #include <boost/mpl/sizeof.hpp> #include <boost/fusion/include/as_vector.hpp> #include <boost/fusion/adapted/mpl.hpp> #include <iostream>
int main() { namespace mpl = boost::mpl; namespace fusion = boost::fusion;
typedef mpl::vector<short, int, short> types; typedef mpl::sort<types, mpl::less< mpl::sizeof_<mpl::_1> , mpl::sizeof_<mpl::_2> > >::type sorted_types; typedef fusion::result_of::as_vector<sorted_types>::type tuple;
tuple t; std::cout << sizeof(t) << std::endl; // 8 instead of 12 }
This appears to work.
That's fantastic! Thank you for your recommendation.
You probably need to be able to access the final tuple with the original indices though, which is a bit more involved. #include <boost/mpl/sort.hpp> #include <boost/mpl/vector.hpp> #include <boost/mpl/range_c.hpp> #include <boost/mpl/transform.hpp> #include <boost/mpl/front.hpp> #include <boost/mpl/back.hpp> #include <boost/mpl/zip_view.hpp> #include <boost/mpl/copy.hpp> #include <boost/mpl/sizeof.hpp> #include <boost/mpl/at.hpp> #include <boost/fusion/include/as_vector.hpp> #include <boost/fusion/include/at.hpp> #include <boost/fusion/adapted/mpl.hpp> #include <iostream> int main() { namespace mpl = boost::mpl; namespace fusion = boost::fusion; typedef mpl::vector<short, int, short> types; typedef mpl::copy< mpl::zip_view< mpl::vector< types , mpl::range_c<long, 0L, mpl::size<types>::value> > > , mpl::back_inserter< mpl::vector0<> > >::type indexes_types; typedef mpl::sort< indexes_types , mpl::less< mpl::sizeof_< mpl::front<mpl::_1> > , mpl::sizeof_< mpl::front<mpl::_2> > > >::type indexes_types_sorted; typedef mpl::transform< indexes_types_sorted , mpl::front<mpl::_1> >::type sorted_types; typedef mpl::transform< indexes_types_sorted , mpl::back<mpl::_1> >::type sorted_indexes; typedef fusion::result_of::as_vector<sorted_types>::type tuple; tuple t; std::cout << sizeof( fusion::at_c<mpl::at_c<sorted_indexes, 0>::type::value>(t) ) << std::endl; std::cout << sizeof( fusion::at_c<mpl::at_c<sorted_indexes, 1>::type::value>(t) ) << std::endl; std::cout << sizeof( fusion::at_c<mpl::at_c<sorted_indexes, 2>::type::value>(t) ) << std::endl; } This could make an interesting addition to Boost.Fusion. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost