ceph/src/boost/libs/hana/include/boost/hana/core/default.hpp

   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