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/chain.hpp> 7 #include <boost/hana/config.hpp> 8 #include <boost/hana/equal.hpp> 9 #include <boost/hana/flatten.hpp> 10 #include <boost/hana/optional.hpp> 11 namespace hana = boost::hana; 12 13 main()14int main() { 15 BOOST_HANA_CONSTEXPR_LAMBDA auto inc = [](auto x) { 16 return hana::just(x + 1); 17 }; 18 19 BOOST_HANA_CONSTEXPR_CHECK(hana::chain(hana::just(1), inc) == hana::just(2)); 20 BOOST_HANA_CONSTANT_CHECK(hana::chain(hana::nothing, inc) == hana::nothing); 21 22 BOOST_HANA_CONSTEXPR_CHECK(hana::flatten(hana::just(hana::just(2))) == hana::just(2)); 23 } 24