ceph/src/boost/libs/hana/test/integral_constant/std_api.cpp

   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 #include <boost/hana/integral_constant.hpp>
   6
   7 #include <cstddef>
   8 #include <type_traits>
   9 namespace hana = boost::hana;
  10
  11
  12 // operator()
  13 static_assert(hana::size_c<0>() == 0, "");
  14 static_assert(hana::size_c<1>() == 1, "");
  15 static_assert(hana::int_c<-3>() == -3, "");
  16
  17 // decltype(operator())
  18 static_assert(std::is_same<decltype(hana::size_c<0>()), std::size_t>{}, "");
  19 static_assert(std::is_same<decltype(hana::int_c<-3>()), int>{}, "");
  20
  21 // conversions
  22 constexpr std::size_t a = hana::size_c<0>, b = hana::size_c<1>;
  23 static_assert(a == 0 && b == 1, "");
  24
  25 constexpr int c = hana::int_c<0>, d = hana::int_c<-3>;
  26 static_assert(c == 0 && d == -3, "");
  27
  28 // nested ::value
  29 static_assert(decltype(hana::int_c<1>)::value == 1, "");
  30
  31 // nested ::type
  32 static_assert(std::is_same<
  33     decltype(hana::int_c<1>)::type,
  34     std::remove_cv_t<decltype(hana::int_c<1>)>
  35 >{}, "");
  36
  37 // nested ::value_type
  38 static_assert(std::is_same<decltype(hana::int_c<1>)::value_type, int>{}, "");
  39
  40 // inherits from std::integral_constant
  41 static_assert(std::is_base_of<std::integral_constant<int, 3>,
  42                               hana::integral_constant<int, 3>>{}, "");
  43
  44 int main() { }