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/config.hpp>
7 #include <boost/hana/core/to.hpp>
8 #include <boost/hana/equal.hpp>
9 #include <boost/hana/find.hpp>
10 #include <boost/hana/functional/id.hpp>
11 #include <boost/hana/fwd/accessors.hpp>
12 #include <boost/hana/integral_constant.hpp>
13 #include <boost/hana/not_equal.hpp>
14 #include <boost/hana/pair.hpp>
15 #include <boost/hana/string.hpp>
16 #include <boost/hana/tuple.hpp>
17
18 #include <string>
19 #include <utility>
20 namespace hana = boost::hana;
21
22
23 //! [main]
24 struct Person {
25 std::string name;
26 int age;
27 };
28
29 // The keys can be anything as long as they are compile-time comparable.
30 constexpr auto name = hana::integral_c<std::string Person::*, &Person::name>;
31 constexpr auto age = hana::string_c<'a', 'g', 'e'>;
32
33 namespace boost { namespace hana {
34 template <>
35 struct accessors_impl<Person> {
applyboost::hana::accessors_impl36 static BOOST_HANA_CONSTEXPR_LAMBDA auto apply() {
37 return make_tuple(
38 make_pair(name, [](auto&& p) -> decltype(auto) {
39 return id(std::forward<decltype(p)>(p).name);
40 }),
41 make_pair(age, [](auto&& p) -> decltype(auto) {
42 return id(std::forward<decltype(p)>(p).age);
43 })
44 );
45 }
46 };
47 }}
48 //! [main]
49
main()50 int main() {
51 Person john{"John", 30}, bob{"Bob", 40};
52 BOOST_HANA_RUNTIME_CHECK(hana::equal(john, john));
53 BOOST_HANA_RUNTIME_CHECK(hana::not_equal(john, bob));
54
55 BOOST_HANA_RUNTIME_CHECK(hana::find(john, name) == hana::just("John"));
56 BOOST_HANA_RUNTIME_CHECK(hana::find(john, age) == hana::just(30));
57 BOOST_HANA_CONSTANT_CHECK(hana::find(john, BOOST_HANA_STRING("foo")) == hana::nothing);
58
59 BOOST_HANA_RUNTIME_CHECK(hana::to_tuple(john) == hana::make_tuple(
60 hana::make_pair(name, "John"),
61 hana::make_pair(age, 30)
62 ));
63 }
64