51 lines
1.4 KiB
C++
51 lines
1.4 KiB
C++
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/*!
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@file
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Forward declares `boost::hana::keys`.
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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_FWD_KEYS_HPP
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#define BOOST_HANA_FWD_KEYS_HPP
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#include <boost/hana/config.hpp>
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#include <boost/hana/core/when.hpp>
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BOOST_HANA_NAMESPACE_BEGIN
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// Note: This function is documented per datatype/concept only.
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//! @cond
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template <typename T, typename = void>
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struct keys_impl : keys_impl<T, when<true>> { };
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//! @endcond
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struct keys_t {
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template <typename Map>
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constexpr auto operator()(Map&& map) const;
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};
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constexpr keys_t keys{};
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//! Returns a `Sequence` containing the name of the members of
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//! the data structure.
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//! @ingroup group-Struct
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//!
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//! Given a `Struct` object, `keys` returns a `Sequence` containing the
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//! name of all the members of the `Struct`, in the same order as they
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//! appear in the `accessors` sequence.
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//!
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//!
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//! Example
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//! -------
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//! @include example/struct/keys.cpp
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#ifdef BOOST_HANA_DOXYGEN_INVOKED
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constexpr auto keys = [](auto&& object) {
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return implementation_defined;
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};
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#endif
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BOOST_HANA_NAMESPACE_END
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#endif // !BOOST_HANA_FWD_KEYS_HPP
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