ceph/src/boost/libs/hana/example/optional/monad_plus.cpp

   1 // Copyright Louis Dionne 2013-2016
   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/concat.hpp>
   7 #include <boost/hana/empty.hpp>
   8 #include <boost/hana/equal.hpp>
   9 #include <boost/hana/optional.hpp>
  10 namespace hana = boost::hana;
  11
  12
  13 static_assert(hana::concat(hana::nothing, hana::just('x')) == hana::just('x'), "");
  14 BOOST_HANA_CONSTANT_CHECK(hana::concat(hana::nothing, hana::nothing) == hana::nothing);
  15 static_assert(hana::concat(hana::just('x'), hana::just('y')) == hana::just('x'), "");
  16 BOOST_HANA_CONSTANT_CHECK(hana::empty<hana::optional_tag>() == hana::nothing);
  17
  18 int main() { }