]>
Commit | Line | Data |
---|---|---|
b32b8144 | 1 | // Copyright Louis Dionne 2013-2017 |
7c673cae FG |
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/equal.hpp> | |
8 | #include <boost/hana/fold_right.hpp> | |
9 | #include <boost/hana/if.hpp> | |
10 | #include <boost/hana/less.hpp> | |
11 | #include <boost/hana/prepend.hpp> | |
12 | #include <boost/hana/tuple.hpp> | |
13 | namespace hana = boost::hana; | |
14 | using namespace hana::literals; | |
15 | ||
16 | ||
17 | int main() { | |
18 | constexpr auto numbers = hana::tuple_c<int, 5, -1, 0, -7, -2, 0, -5, 4>; | |
19 | constexpr auto negatives = hana::tuple_c<int, -1, -7, -2, -5>; | |
20 | ||
21 | BOOST_HANA_CONSTEXPR_LAMBDA auto keep_negatives = [](auto n, auto acc) { | |
22 | return hana::if_(n < 0_c, hana::prepend(acc, n), acc); | |
23 | }; | |
24 | ||
25 | BOOST_HANA_CONSTANT_CHECK(hana::fold_right(numbers, hana::tuple_c<int>, keep_negatives) == negatives); | |
26 | } |