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28 lines
739 B
C++
28 lines
739 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/assert.hpp>
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#include <boost/hana/detail/constexpr.hpp>
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#include <boost/hana/integral.hpp>
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#include <boost/hana/maybe.hpp>
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using namespace boost::hana;
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//! [main]
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BOOST_HANA_CONSTEXPR_LAMBDA auto even = [](auto x) {
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return x % int_<2> == int_<0>;
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};
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BOOST_HANA_CONSTEXPR_LAMBDA auto half = [](auto x) {
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return x / int_<2>;
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};
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BOOST_HANA_CONSTANT_ASSERT(only_when(even, half, int_<4>) == just(int_<2>));
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BOOST_HANA_CONSTANT_ASSERT(only_when(even, half, int_<3>) == nothing);
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//! [main]
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int main() { (void)even; (void)half; }
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