hana/example/ext/boost/mpl/list/foldable.cpp
2017-01-07 14:14:18 -08:00

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986 B
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/assert.hpp>
#include <boost/hana/equal.hpp>
#include <boost/hana/ext/boost/mpl/list.hpp>
#include <boost/hana/ext/std/integral_constant.hpp>
#include <boost/hana/fold_left.hpp>
#include <boost/hana/if.hpp>
#include <boost/hana/integral_constant.hpp>
#include <boost/hana/plus.hpp>
#include <boost/hana/type.hpp>
#include <boost/mpl/list.hpp>
#include <type_traits>
namespace hana = boost::hana;
namespace mpl = boost::mpl;
auto types = mpl::list<long, float, short, float, long, long double>{};
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>);
int main() { }