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28 lines
881 B
C++
28 lines
881 B
C++
/*
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@copyright Louis Dionne 2014
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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*/
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#include <boost/hana/detail/constexpr.hpp>
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#include <boost/hana/detail/static_assert.hpp>
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#include <boost/hana/integer_list.hpp>
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#include <boost/hana/integral.hpp>
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#include <boost/hana/logical.hpp>
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using namespace boost::hana;
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using namespace literals;
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int main() {
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//! [main]
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BOOST_HANA_CONSTEXPR_LAMBDA auto numbers = integer_list<int, 5, -1, 0, -7, -2, 0, -5, 4>;
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BOOST_HANA_CONSTEXPR_LAMBDA auto negatives = integer_list<int, -1, -7, -2, -5>;
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BOOST_HANA_CONSTEXPR_LAMBDA auto keep_negatives = [](auto n, auto acc) {
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return if_(n < 0_c, cons(n, acc), acc);
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};
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BOOST_HANA_STATIC_ASSERT(foldr(keep_negatives, integer_list<int>, numbers) == negatives);
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//! [main]
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}
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