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- // 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/config.hpp>
- #include <boost/hana/equal.hpp>
- #include <boost/hana/ext/boost/mpl/vector.hpp>
- #include <boost/hana/ext/std/integral_constant.hpp>
- #include <boost/hana/integral_constant.hpp>
- #include <boost/hana/plus.hpp>
- #include <boost/hana/tuple.hpp>
- #include <boost/mpl/fold.hpp>
- #include <boost/mpl/if.hpp>
- #include <boost/mpl/int.hpp>
- #include <boost/mpl/next.hpp>
- #include <boost/mpl/placeholders.hpp>
- #include <boost/mpl/vector.hpp>
- #include <type_traits>
- namespace hana = boost::hana;
- namespace mpl = boost::mpl;
- namespace with_mpl {
- //! [mpl]
- using types = mpl::vector<long, float, short, float, long, long double>;
- using number_of_floats = mpl::fold<
- types,
- mpl::int_<0>,
- mpl::if_<std::is_floating_point<mpl::_2>,
- mpl::next<mpl::_1>,
- mpl::_1
- >
- >::type;
- static_assert(number_of_floats::value == 3, "");
- //! [mpl]
- }
- namespace with_hana {
- //! [hana]
- constexpr auto types = hana::tuple_t<long, float, short, float, long, long double>;
- BOOST_HANA_CONSTEXPR_LAMBDA auto number_of_floats = hana::fold_left(
- types,
- hana::int_c<0>,
- [](auto count, auto t) {
- return hana::if_(hana::trait<std::is_floating_point>(t),
- count + hana::int_c<1>,
- count
- );
- }
- );
- BOOST_HANA_CONSTANT_CHECK(number_of_floats == hana::int_c<3>);
- //! [hana]
- }
- int main() { }
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