ceph/src/boost/libs/hana/example/define_struct.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/accessors.hpp>
   6 #include <boost/hana/assert.hpp>
   7 #include <boost/hana/core/to.hpp>
   8 #include <boost/hana/define_struct.hpp>
   9 #include <boost/hana/equal.hpp>
  10 #include <boost/hana/find.hpp>
  11 #include <boost/hana/first.hpp>
  12 #include <boost/hana/map.hpp>
  13 #include <boost/hana/not_equal.hpp>
  14 #include <boost/hana/optional.hpp>
  15 #include <boost/hana/pair.hpp>
  16 #include <boost/hana/string.hpp>
  17 #include <boost/hana/transform.hpp>
  18 #include <boost/hana/tuple.hpp>
  19
  20 #include <string>
  21 namespace hana = boost::hana;
  22
  23
  24 struct Person {
  25     BOOST_HANA_DEFINE_STRUCT(Person,
  26         (std::string, name),
  27         (int, age)
  28     );
  29 };
  30
  31 // The member names are hana::strings:
  32 auto names = hana::transform(hana::accessors<Person>(), hana::first);
  33 BOOST_HANA_CONSTANT_CHECK(
  34     names == hana::make_tuple(BOOST_HANA_STRING("name"), BOOST_HANA_STRING("age"))
  35 );
  36
  37 int main() {
  38     Person john{"John", 30}, bob{"Bob", 40};
  39     BOOST_HANA_RUNTIME_CHECK(hana::equal(john, john));
  40     BOOST_HANA_RUNTIME_CHECK(hana::not_equal(john, bob));
  41
  42     BOOST_HANA_RUNTIME_CHECK(hana::find(john, BOOST_HANA_STRING("name")) == hana::just("John"));
  43     BOOST_HANA_RUNTIME_CHECK(hana::find(john, BOOST_HANA_STRING("age")) == hana::just(30));
  44     BOOST_HANA_CONSTANT_CHECK(hana::find(john, BOOST_HANA_STRING("foo")) == hana::nothing);
  45
  46     BOOST_HANA_RUNTIME_CHECK(hana::to_tuple(john) == hana::make_tuple(
  47         hana::make_pair(BOOST_HANA_STRING("name"), "John"),
  48         hana::make_pair(BOOST_HANA_STRING("age"), 30)
  49     ));
  50
  51     BOOST_HANA_RUNTIME_CHECK(hana::to_map(john) == hana::make_map(
  52         hana::make_pair(BOOST_HANA_STRING("name"), "John"),
  53         hana::make_pair(BOOST_HANA_STRING("age"), 30)
  54     ));
  55 }