Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards


    Copyright (c) 2009 Christopher Schmidt

    Distributed under the Boost Software License, Version 1.0. (See accompanying
    file LICENSE_1_0.txt or copy at


#include <boost/fusion/support/config.hpp>
#include <boost/fusion/support/tag_of.hpp>

namespace boost { namespace fusion
    struct iterator_facade_tag;

    namespace extension
        template <typename>
        struct key_of_impl;

        template <>
        struct key_of_impl<iterator_facade_tag>
            template <typename It>
            struct apply
              : It::template key_of<It>

    namespace result_of
        template <typename It>
        struct key_of
          : extension::key_of_impl<typename traits::tag_of<It>::type>::
                template apply<It>