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 main()12int 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 } 21