ceph/src/boost/libs/hana/test/_include/support/minimal_product.hpp

   1 // Copyright Louis Dionne 2013-2017
   2 // Distributed under the Boost Software License, Version 1.0.
   3 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   4
   5 #ifndef TEST_SUPPORT_MINIMAL_PRODUCT_HPP
   6 #define TEST_SUPPORT_MINIMAL_PRODUCT_HPP
   7
   8 #include <boost/hana/fwd/core/make.hpp>
   9 #include <boost/hana/fwd/first.hpp>
  10 #include <boost/hana/fwd/second.hpp>
  11
  12 #include <type_traits>
  13
  14
  15 struct MinimalProduct;
  16
  17 template <typename X, typename Y>
  18 struct product_t {
  19     X fst;
  20     Y snd;
  21     using hana_tag = MinimalProduct;
  22 };
  23
  24 struct make_minimal_product {
  25     template <typename T, typename U>
  26     constexpr product_t<typename std::decay<T>::type,
  27                         typename std::decay<U>::type>
  28     operator()(T&& t, U&& u) const {
  29         return {static_cast<T&&>(t), static_cast<U&&>(u)};
  30     }
  31 };
  32
  33 constexpr make_minimal_product minimal_product{};
  34
  35 namespace boost { namespace hana {
  36     //////////////////////////////////////////////////////////////////////////
  37     // Product
  38     //////////////////////////////////////////////////////////////////////////
  39     template <>
  40     struct make_impl<MinimalProduct> {
  41         template <typename X, typename Y>
  42         static constexpr auto apply(X x, Y y)
  43         { return ::minimal_product(x, y); }
  44     };
  45
  46     template <>
  47     struct first_impl<MinimalProduct> {
  48         template <typename P>
  49         static constexpr decltype(auto) apply(P&& p)
  50         { return p.fst; }
  51     };
  52
  53     template <>
  54     struct second_impl<MinimalProduct> {
  55         template <typename P>
  56         static constexpr decltype(auto) apply(P&& p)
  57         { return p.snd; }
  58     };
  59 }} // end namespace boost::hana
  60
  61 #endif // !TEST_SUPPORT_MINIMAL_PRODUCT_HPP