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[ceph.git] / ceph / src / boost / libs / hana / example / struct / foldable.cpp

// 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)
    );
}