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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)
5 #include <boost/hana/first.hpp>
6 #include <boost/hana/functional/on.hpp>
7 #include <boost/hana/integral_constant.hpp>
8 #include <boost/hana/less.hpp>
9 #include <boost/hana/pair.hpp>
10 #include <boost/hana/plus.hpp>
11 #include <boost/hana/sort.hpp>
12 #include <boost/hana/tuple.hpp>
13 #include <boost/hana/type.hpp>
14 namespace hana
= boost::hana
;
18 constexpr auto sorted
= hana::sort
.by(hana::less
^hana::on
^ hana::first
, hana::make_tuple(
19 hana::make_pair(hana::int_c
<3>, 'x'),
20 hana::make_pair(hana::int_c
<1>, hana::type_c
<void>),
21 hana::make_pair(hana::int_c
<2>, 9876)
24 static_assert(sorted
== hana::make_tuple(
25 hana::make_pair(hana::int_c
<1>, hana::type_c
<void>),
26 hana::make_pair(hana::int_c
<2>, 9876),
27 hana::make_pair(hana::int_c
<3>, 'x')
31 // function call syntax
32 constexpr auto x
= hana::make_pair(1, 2);
33 constexpr auto y
= hana::make_pair(10, 20);
34 static_assert(hana::on(hana::plus
, hana::first
)(x
, y
) == 1 + 10, "");