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/define_struct.hpp>
7 #include <boost/hana/fold_left.hpp>
8 #include <boost/hana/second.hpp>
9 namespace hana = boost::hana;
10
11
12 struct Kitten {
13 BOOST_HANA_DEFINE_STRUCT(Kitten,
14 (int, extremely_cute),
15 (int, cute),
16 (int, not_so_cute)
17 );
18 };
19
main()20 int main() {
21 constexpr Kitten kitten{5, 10, 0};
22
23 BOOST_HANA_CONSTEXPR_CHECK(
24 hana::fold_left(kitten, 0, [](auto total, auto member) {
25 // first(member) is the name of the member, here
26 // "extremely_cute", or "cute" or "not_so_cute",
27 // and second(member) is its value.
28 return hana::second(member) + total;
29 }) == (5 + 10 + 0)
30 );
31 }
32