hana/example/ap.cpp
2017-01-07 14:14:18 -08:00

49 lines
1.4 KiB
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/ap.hpp>
#include <boost/hana/assert.hpp>
#include <boost/hana/config.hpp>
#include <boost/hana/equal.hpp>
#include <boost/hana/optional.hpp>
#include <boost/hana/tuple.hpp>
#include <functional>
namespace hana = boost::hana;
int main() {
// with tuples
static_assert(
hana::ap(hana::make_tuple(std::plus<>{}), hana::make_tuple(1, 2),
hana::make_tuple(3, 4, 5))
==
hana::make_tuple(
1 + 3, 1 + 4, 1 + 5,
2 + 3, 2 + 4, 2 + 5
)
, "");
// with optional values
BOOST_HANA_CONSTEXPR_LAMBDA auto multiply = [](auto a, auto b, auto c) {
return a * b * c;
};
BOOST_HANA_CONSTEXPR_CHECK(
hana::ap(hana::just(multiply), hana::just(1),
hana::just(2),
hana::just(3))
==
hana::just(1 * 2 * 3)
);
BOOST_HANA_CONSTANT_CHECK(
hana::ap(hana::just(multiply), hana::just(1),
hana::nothing,
hana::just(3))
==
hana::nothing
);
}