1 /*! 2 @file 3 Defines `boost::hana::default_` and `boost::hana::is_default`. 4 5 @copyright Louis Dionne 2013-2016 6 Distributed under the Boost Software License, Version 1.0. 7 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) 8 */ 9 10 #ifndef BOOST_HANA_CORE_DEFAULT_HPP 11 #define BOOST_HANA_CORE_DEFAULT_HPP 12 13 #include <boost/hana/fwd/core/default.hpp> 14 15 #include <boost/hana/config.hpp> 16 17 #include <type_traits> 18 19 20 BOOST_HANA_NAMESPACE_BEGIN 21 template <typename Method, typename> 22 struct is_default : std::false_type { }; 23 24 template <typename Method> 25 struct is_default<Method, decltype((void) 26 static_cast<default_>(*(Method*)0) 27 )> 28 : std::true_type 29 { }; 30 BOOST_HANA_NAMESPACE_END 31 32 #endif // !BOOST_HANA_CORE_DEFAULT_HPP 33