hana/example/struct/foldable.cpp
2018-11-09 00:25:30 -08:00

32 lines
903 B
C++

// Copyright Louis Dionne 2013-2017
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
#include <boost/hana/assert.hpp>
#include <boost/hana/define_struct.hpp>
#include <boost/hana/fold_left.hpp>
#include <boost/hana/second.hpp>
namespace hana = boost::hana;
struct Kitten {
BOOST_HANA_DEFINE_STRUCT(Kitten,
(int, extremely_cute),
(int, cute),
(int, not_so_cute)
);
};
int main() {
constexpr Kitten kitten{5, 10, 0};
BOOST_HANA_CONSTEXPR_CHECK(
hana::fold_left(kitten, 0, [](auto total, auto member) {
// first(member) is the name of the member, here
// "extremely_cute", or "cute" or "not_so_cute",
// and second(member) is its value.
return hana::second(member) + total;
}) == (5 + 10 + 0)
);
}