| // Copyright Daniel Wallin, David Abrahams 2010. |
| // 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_MAYBE_050329_HPP |
| #define BOOST_PARAMETER_IS_MAYBE_050329_HPP |
| |
| namespace boost { namespace parameter { namespace aux { |
| |
| struct maybe_base |
| { |
| }; |
| }}} // namespace boost::parameter::aux |
| |
| #if defined(BOOST_PARAMETER_CAN_USE_MP11) |
| #include <type_traits> |
| |
| namespace boost { namespace parameter { namespace aux { |
| |
| template <typename T> |
| using is_maybe = ::std::is_base_of< |
| ::boost::parameter::aux::maybe_base |
| , typename ::std::remove_const<T>::type |
| >; |
| }}} // namespace boost::parameter::aux |
| |
| #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) |
| #include <boost/mpl/bool.hpp> |
| #include <boost/mpl/if.hpp> |
| #include <boost/type_traits/is_base_of.hpp> |
| #include <boost/type_traits/remove_const.hpp> |
| |
| namespace boost { namespace parameter { namespace aux { |
| |
| template <typename T> |
| struct is_maybe |
| : ::boost::mpl::if_< |
| ::boost::is_base_of< |
| ::boost::parameter::aux::maybe_base |
| , typename ::boost::remove_const<T>::type |
| > |
| , ::boost::mpl::true_ |
| , ::boost::mpl::false_ |
| >::type |
| { |
| }; |
| }}} // namespace boost::parameter::aux |
| |
| #endif // BOOST_PARAMETER_CAN_USE_MP11 |
| #endif // include guard |
| |