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f51cf556 | 1 | // Copyright Louis Dionne 2013-2022 |
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/ext/boost/mpl/vector.hpp> | |
9 | #include <boost/hana/ext/std/integral_constant.hpp> | |
10 | #include <boost/hana/integral_constant.hpp> | |
11 | #include <boost/hana/plus.hpp> | |
12 | #include <boost/hana/tuple.hpp> | |
13 | ||
14 | #include <boost/mpl/fold.hpp> | |
15 | #include <boost/mpl/if.hpp> | |
16 | #include <boost/mpl/int.hpp> | |
17 | #include <boost/mpl/next.hpp> | |
18 | #include <boost/mpl/placeholders.hpp> | |
19 | #include <boost/mpl/vector.hpp> | |
20 | ||
21 | #include <type_traits> | |
22 | namespace hana = boost::hana; | |
23 | namespace mpl = boost::mpl; | |
24 | ||
25 | ||
26 | namespace with_mpl { | |
27 | //! [mpl] | |
28 | using types = mpl::vector<long, float, short, float, long, long double>; | |
29 | using number_of_floats = mpl::fold< | |
30 | types, | |
31 | mpl::int_<0>, | |
32 | mpl::if_<std::is_floating_point<mpl::_2>, | |
33 | mpl::next<mpl::_1>, | |
34 | mpl::_1 | |
35 | > | |
36 | >::type; | |
37 | static_assert(number_of_floats::value == 3, ""); | |
38 | //! [mpl] | |
39 | } | |
40 | ||
41 | namespace with_hana { | |
42 | //! [hana] | |
43 | constexpr auto types = hana::tuple_t<long, float, short, float, long, long double>; | |
44 | BOOST_HANA_CONSTEXPR_LAMBDA auto number_of_floats = hana::fold_left( | |
45 | types, | |
46 | hana::int_c<0>, | |
47 | [](auto count, auto t) { | |
48 | return hana::if_(hana::trait<std::is_floating_point>(t), | |
49 | count + hana::int_c<1>, | |
50 | count | |
51 | ); | |
52 | } | |
53 | ); | |
54 | BOOST_HANA_CONSTANT_CHECK(number_of_floats == hana::int_c<3>); | |
55 | //! [hana] | |
56 | } | |
57 | ||
58 | int main() { } |