ceph/src/boost/libs/hana/example/optional/make.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/assert.hpp>
   6 #include <boost/hana/core/make.hpp>
   7 #include <boost/hana/equal.hpp>
   8 #include <boost/hana/optional.hpp>
   9 namespace hana = boost::hana;
  10
  11
  12 int main() {
  13     constexpr auto x = hana::make<hana::optional_tag>();
  14     BOOST_HANA_CONSTANT_CHECK(x == hana::make_optional());
  15     BOOST_HANA_CONSTANT_CHECK(hana::is_nothing(x));
  16
  17     constexpr auto just_x = hana::make<hana::optional_tag>('x');
  18     static_assert(just_x == hana::make_optional('x'), "");
  19     BOOST_HANA_CONSTANT_CHECK(hana::is_just(just_x));
  20 }