...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::pop_front::result<This(Expr &)>
// In header: <boost/proto/fusion.hpp> template<typename This, typename Expr> struct result<This(Expr &)> : fusion::result_of::pop_front< Expr > { };