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hana/test/maybe/foldable/lazy_foldr.cpp
2014-06-26 01:12:37 -04:00

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736 B
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/*
@copyright Louis Dionne 2014
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/maybe.hpp>
#include <boost/hana/detail/constexpr.hpp>
#include <boost/hana/detail/static_assert.hpp>
#include <boost/hana/integral.hpp>
#include <tuple>
using namespace boost::hana;
BOOST_HANA_CONSTEXPR_LAMBDA auto f = [](auto ...x) {
return std::make_tuple(x...);
};
BOOST_HANA_CONSTEXPR_LAMBDA auto lf = [](auto ...x) {
return f(x()...);
};
int main() {
BOOST_HANA_STATIC_ASSERT(lazy_foldr(lf, int_<0>, nothing) == int_<0>);
BOOST_HANA_STATIC_ASSERT(lazy_foldr(lf, int_<0>, just(int_<1>)) == f(int_<1>, int_<0>));
}