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- // Copyright David Abrahams, Daniel Wallin 2003.
- // Distributed under the Boost Software License, Version 1.0.
- // (See accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- #ifndef BOOST_PARAMETER_AUX_PACK_TAG_TYPE_HPP
- #define BOOST_PARAMETER_AUX_PACK_TAG_TYPE_HPP
- namespace boost { namespace parameter { namespace aux {
- // helper for tag_type<...>, below.
- template <typename T>
- struct get_tag_type0
- {
- typedef typename T::key_type type;
- };
- }}} // namespace boost::parameter::aux
- #include <boost/parameter/deduced.hpp>
- #include <boost/parameter/config.hpp>
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- #include <boost/mp11/utility.hpp>
- #else
- #include <boost/mpl/eval_if.hpp>
- #endif
- namespace boost { namespace parameter { namespace aux {
- template <typename T>
- struct get_tag_type
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- : ::boost::mp11::mp_if<
- #else
- : ::boost::mpl::eval_if<
- #endif
- ::boost::parameter::aux::is_deduced0<T>
- , ::boost::parameter::aux::get_tag_type0<typename T::key_type>
- , ::boost::parameter::aux::get_tag_type0<T>
- >
- {
- };
- }}} // namespace boost::parameter::aux
- #include <boost/parameter/required.hpp>
- #include <boost/parameter/optional.hpp>
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- #include <boost/mp11/integral.hpp>
- namespace boost { namespace parameter { namespace aux {
- template <typename T>
- using tag_type = ::boost::mp11::mp_if<
- ::boost::mp11::mp_if<
- ::boost::parameter::aux::is_optional<T>
- , ::boost::mp11::mp_true
- , ::boost::parameter::aux::is_required<T>
- >
- , ::boost::parameter::aux::get_tag_type<T>
- , ::boost::mp11::mp_identity<T>
- >;
- }}} // namespace boost::parameter::aux
- #else // !defined(BOOST_PARAMETER_CAN_USE_MP11)
- #include <boost/mpl/bool.hpp>
- #include <boost/mpl/if.hpp>
- #include <boost/mpl/identity.hpp>
- namespace boost { namespace parameter { namespace aux {
- template <typename T>
- struct tag_type
- : ::boost::mpl::eval_if<
- typename ::boost::mpl::if_<
- ::boost::parameter::aux::is_optional<T>
- , ::boost::mpl::true_
- , ::boost::parameter::aux::is_required<T>
- >::type
- , ::boost::parameter::aux::get_tag_type<T>
- , ::boost::mpl::identity<T>
- >
- {
- };
- }}} // namespace boost::parameter::aux
- #endif // BOOST_PARAMETER_CAN_USE_MP11
- #endif // include guard
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