/*! @file Defines `boost::hana::members`. @copyright Louis Dionne 2013-2016 Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) */ #ifndef BOOST_HANA_MEMBERS_HPP #define BOOST_HANA_MEMBERS_HPP #include <boost/hana/fwd/members.hpp> #include <boost/hana/accessors.hpp> #include <boost/hana/concept/struct.hpp> #include <boost/hana/config.hpp> #include <boost/hana/core/dispatch.hpp> #include <boost/hana/second.hpp> #include <boost/hana/transform.hpp> BOOST_HANA_NAMESPACE_BEGIN //! @cond template <typename Object> constexpr auto members_t::operator()(Object&& object) const { using S = typename hana::tag_of<Object>::type; using Members = BOOST_HANA_DISPATCH_IF(members_impl<S>, hana::Struct<S>::value ); #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS static_assert(hana::Struct<S>::value, "hana::members(object) requires 'object' to be a Struct"); #endif return Members::apply(static_cast<Object&&>(object)); } //! @endcond namespace struct_detail { template <typename Holder, typename Forward> struct members_helper { Holder object; template <typename Accessor> constexpr decltype(auto) operator()(Accessor&& accessor) const { return hana::second(static_cast<Accessor&&>(accessor))( static_cast<Forward>(object) ); } }; } template <typename S, bool condition> struct members_impl<S, when<condition>> : default_ { template <typename Object> static constexpr auto apply(Object&& object) { return hana::transform(hana::accessors<S>(), struct_detail::members_helper<Object&, Object&&>{object} ); } }; BOOST_HANA_NAMESPACE_END #endif // !BOOST_HANA_MEMBERS_HPP