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- // Copyright Daniel Wallin, David Abrahams 2005.
- // Copyright Cromwell D. Enage 2017.
- // 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_IS_TAGGED_ARGUMENT_HPP
- #define BOOST_PARAMETER_IS_TAGGED_ARGUMENT_HPP
- namespace boost { namespace parameter { namespace aux {
- struct tagged_argument_base
- {
- };
- }}} // namespace boost::parameter::aux
- #include <boost/parameter/config.hpp>
- #include <boost/mpl/bool.hpp>
- #include <boost/mpl/if.hpp>
- #if defined(BOOST_PARAMETER_HAS_PERFECT_FORWARDING) || \
- (0 < BOOST_PARAMETER_EXPONENTIAL_OVERLOAD_THRESHOLD_ARITY)
- #include <boost/type_traits/is_base_of.hpp>
- #include <boost/type_traits/remove_const.hpp>
- #include <boost/type_traits/remove_reference.hpp>
- namespace boost { namespace parameter { namespace aux {
- // This metafunction identifies tagged_argument specializations
- // and their derived classes.
- template <typename T>
- struct is_tagged_argument
- : ::boost::mpl::if_<
- // Cannot use is_convertible<> to check if T is derived from
- // tagged_argument_base. -- Cromwell D. Enage
- ::boost::is_base_of<
- ::boost::parameter::aux::tagged_argument_base
- , typename ::boost::remove_const<
- typename ::boost::remove_reference<T>::type
- >::type
- >
- , ::boost::mpl::true_
- , ::boost::mpl::false_
- >::type
- {
- };
- }}} // namespace boost::parameter::aux
- #else // no perfect forwarding support and no exponential overloads
- #include <boost/type_traits/is_convertible.hpp>
- #include <boost/type_traits/is_lvalue_reference.hpp>
- namespace boost { namespace parameter { namespace aux {
- template <typename T>
- struct is_tagged_argument_aux
- : ::boost::is_convertible<
- T*
- , ::boost::parameter::aux::tagged_argument_base const*
- >
- {
- };
- // This metafunction identifies tagged_argument specializations
- // and their derived classes.
- template <typename T>
- struct is_tagged_argument
- : ::boost::mpl::if_<
- ::boost::is_lvalue_reference<T>
- , ::boost::mpl::false_
- , ::boost::parameter::aux::is_tagged_argument_aux<T>
- >::type
- {
- };
- }}} // namespace boost::parameter::aux
- #endif // perfect forwarding support, or exponential overloads
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- #include <type_traits>
- namespace boost { namespace parameter { namespace aux {
- template <typename T>
- using is_tagged_argument_mp11 = ::std::is_base_of<
- ::boost::parameter::aux::tagged_argument_base
- , typename ::std::remove_const<
- typename ::std::remove_reference<T>::type
- >::type
- >;
- }}} // namespace boost::parameter::aux
- #endif // BOOST_PARAMETER_CAN_USE_MP11
- #endif // include guard
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