ceph/src/boost/libs/hana/example/at_key.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/at_key.hpp>
   7 #include <boost/hana/integral_constant.hpp>
   8 #include <boost/hana/map.hpp>
   9 #include <boost/hana/pair.hpp>
  10 #include <boost/hana/type.hpp>
  11
  12 #include <string>
  13 namespace hana = boost::hana;
  14
  15
  16 int main() {
  17     auto m = hana::make_map(
  18         hana::make_pair(hana::type<int>{}, std::string{"int"}),
  19         hana::make_pair(hana::int_<3>{}, std::string{"3"})
  20     );
  21
  22     BOOST_HANA_RUNTIME_CHECK(hana::at_key(m, hana::type<int>{}) == "int");
  23
  24     // usage as operator[]
  25     BOOST_HANA_RUNTIME_CHECK(m[hana::type<int>{}] == "int");
  26     BOOST_HANA_RUNTIME_CHECK(m[hana::int_<3>{}] == "3");
  27 }