...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::proto::functional::at::result<This(Seq, N)>
// In header: <boost/proto/functional/fusion/at.hpp> template<typename This, typename Seq, typename N> struct result<This(Seq, N)> : fusion::result_of::at< typename boost::remove_reference<Seq>::type , typename boost::remove_const<typename boost::remove_reference<N>::type>::type > { };