40 lines
1.3 KiB
C++
40 lines
1.3 KiB
C++
// Copyright Louis Dionne 2013-2017
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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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#include <boost/hana/assert.hpp>
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#include <boost/hana/equal.hpp>
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#include <boost/hana/equal.hpp>
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#include <boost/hana/ext/std/integral_constant.hpp>
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#include <boost/hana/find_if.hpp>
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#include <boost/hana/functional/compose.hpp>
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#include <boost/hana/optional.hpp>
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#include <boost/hana/tuple.hpp>
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#include <boost/hana/type.hpp>
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#include <type_traits>
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namespace hana = boost::hana;
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// First get the type of the object, and then call the trait on it.
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constexpr auto is_integral = hana::compose(hana::trait<std::is_integral>, hana::typeid_);
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constexpr auto is_class = hana::compose(hana::trait<std::is_class>, hana::typeid_);
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static_assert(
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hana::find_if(hana::make_tuple(1.0, 2, '3'), is_integral) == hana::just(2)
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, "");
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BOOST_HANA_CONSTANT_CHECK(
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hana::find_if(hana::make_tuple(1.0, 2, '3'), is_class) == hana::nothing
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);
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constexpr auto types = hana::tuple_t<char, int, unsigned, long, unsigned long>;
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BOOST_HANA_CONSTANT_CHECK(
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hana::find_if(types, hana::equal.to(hana::type_c<unsigned>)) == hana::just(hana::type_c<unsigned>)
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);
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BOOST_HANA_CONSTANT_CHECK(
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hana::find_if(types, hana::equal.to(hana::type_c<void>)) == hana::nothing
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);
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int main() { }
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