57 lines
1.5 KiB
C++
57 lines
1.5 KiB
C++
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/*!
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@file
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Defines `boost::hana::accessors`.
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@copyright Louis Dionne 2013-2016
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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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#ifndef BOOST_HANA_ACCESSORS_HPP
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#define BOOST_HANA_ACCESSORS_HPP
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#include <boost/hana/fwd/accessors.hpp>
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#include <boost/hana/concept/struct.hpp>
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#include <boost/hana/config.hpp>
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#include <boost/hana/core/dispatch.hpp>
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BOOST_HANA_NAMESPACE_BEGIN
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template <typename S>
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struct accessors_t {
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#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
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static_assert(hana::Struct<S>::value,
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"hana::accessors<S> requires 'S' to be a Struct");
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#endif
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constexpr decltype(auto) operator()() const {
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using Accessors = BOOST_HANA_DISPATCH_IF(accessors_impl<S>,
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hana::Struct<S>::value
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);
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return Accessors::apply();
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}
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};
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template <typename S, bool condition>
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struct accessors_impl<S, when<condition>> : default_ {
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template <typename ...Args>
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static constexpr auto apply(Args&& ...) = delete;
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};
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namespace struct_detail {
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template <typename ...>
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struct is_valid { static constexpr bool value = true; };
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}
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template <typename S>
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struct accessors_impl<S, when<
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struct_detail::is_valid<typename S::hana_accessors_impl>::value
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>>
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: S::hana_accessors_impl
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{ };
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BOOST_HANA_NAMESPACE_END
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#endif // !BOOST_HANA_ACCESSORS_HPP
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