53 lines
1.4 KiB
C++
53 lines
1.4 KiB
C++
// Copyright Daniel Wallin, David Abrahams 2010.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_PARAMETER_IS_MAYBE_050329_HPP
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#define BOOST_PARAMETER_IS_MAYBE_050329_HPP
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namespace boost { namespace parameter { namespace aux {
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struct maybe_base
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{
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};
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}}} // namespace boost::parameter::aux
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#if defined(BOOST_PARAMETER_CAN_USE_MP11)
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#include <type_traits>
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namespace boost { namespace parameter { namespace aux {
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template <typename T>
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using is_maybe = ::std::is_base_of<
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::boost::parameter::aux::maybe_base
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, typename ::std::remove_const<T>::type
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>;
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}}} // namespace boost::parameter::aux
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#else // !defined(BOOST_PARAMETER_CAN_USE_MP11)
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#include <boost/mpl/bool.hpp>
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#include <boost/mpl/if.hpp>
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#include <boost/type_traits/is_base_of.hpp>
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#include <boost/type_traits/remove_const.hpp>
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namespace boost { namespace parameter { namespace aux {
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template <typename T>
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struct is_maybe
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: ::boost::mpl::if_<
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::boost::is_base_of<
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::boost::parameter::aux::maybe_base
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, typename ::boost::remove_const<T>::type
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>
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, ::boost::mpl::true_
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, ::boost::mpl::false_
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>::type
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{
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};
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}}} // namespace boost::parameter::aux
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#endif // BOOST_PARAMETER_CAN_USE_MP11
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#endif // include guard
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