forked from boostorg/fusion
c10b94472d
see http://thread.gmane.org/gmane.comp.lib.boost.devel/255086 Signed-off-by: Kohei Takahashi <flast@flast.jp>
48 lines
1.6 KiB
C++
48 lines
1.6 KiB
C++
/*=============================================================================
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Copyright (c) 2001-2014 Joel de Guzman
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#if !defined(FUSION_RESULT_OF_10272014_0654)
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#define FUSION_RESULT_OF_10272014_0654
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#include <boost/utility/result_of.hpp>
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#if !(defined(BOOST_NO_CXX11_DECLTYPE) || defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES))
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#include <boost/mpl/if.hpp>
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#include <boost/mpl/or.hpp>
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#include <boost/mpl/has_xxx.hpp>
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#endif
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namespace boost { namespace fusion { namespace detail
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{
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// This is a temporary workaround for result_of before we make fusion fully
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// sfinae result_of friendy, which will require some heavy lifting for some
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// low level code. So far this is used only in the fold algorithm. This will
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// be removed once we overhaul fold.
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#if defined(BOOST_NO_CXX11_DECLTYPE) || defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
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template <typename Sig>
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struct result_of_with_decltype : boost::tr1_result_of<Sig> {};
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#else
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BOOST_MPL_HAS_XXX_TRAIT_DEF(result_type)
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BOOST_MPL_HAS_XXX_TEMPLATE_DEF(result)
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template <typename Sig>
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struct result_of_with_decltype;
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template <typename F, typename... Args>
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struct result_of_with_decltype<F(Args...)>
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: mpl::if_<mpl::or_<has_result_type<F>, detail::has_result<F> >,
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boost::tr1_result_of<F(Args...)>,
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boost::detail::cpp0x_result_of<F(Args...)> >::type {};
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#endif
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}}}
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#endif
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