/*============================================================================= Copyright (c) 2007 Tobias Schwinger Use modification and distribution are subject to the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt). ==============================================================================*/ #if !defined(BOOST_FUSION_SUPPORT_DEDUCE_HPP_INCLUDED) #define BOOST_FUSION_SUPPORT_DEDUCE_HPP_INCLUDED #include <boost/fusion/support/config.hpp> #include <boost/core/ref.hpp> #ifndef BOOST_NO_CXX11_HDR_FUNCTIONAL #include <functional> #endif namespace boost { namespace fusion { namespace traits { template <typename T> struct deduce; //----- ---- --- -- - - - - // Non-references pass unchanged template <typename T> struct deduce { typedef T type; }; template <typename T> struct deduce<T const> { typedef T type; }; template <typename T> struct deduce<T volatile> { typedef T type; }; template <typename T> struct deduce<T const volatile> { typedef T type; }; // Keep references on mutable LValues template <typename T> struct deduce<T &> { typedef T & type; }; template <typename T> struct deduce<T volatile&> { typedef T volatile& type; }; // Store away potential RValues template <typename T> struct deduce<T const&> { typedef T type; }; template <typename T> struct deduce<T const volatile&> { typedef T type; }; // Unwrap Boost.RefS (referencee cv is deduced) template <typename T> struct deduce<reference_wrapper<T> & > { typedef T& type; }; template <typename T> struct deduce<reference_wrapper<T> const & > { typedef T& type; }; // Also unwrap C++11 std::ref if available (referencee cv is deduced) #ifndef BOOST_NO_CXX11_HDR_FUNCTIONAL template <typename T> struct deduce<std::reference_wrapper<T> &> { typedef T& type; }; template <typename T> struct deduce<std::reference_wrapper<T> const &> { typedef T& type; }; #endif // Keep references on arrays, even if const template <typename T, int N> struct deduce<T(&)[N]> { typedef T(&type)[N]; }; template <typename T, int N> struct deduce<volatile T(&)[N]> { typedef volatile T(&type)[N]; }; template <typename T, int N> struct deduce<const T(&)[N]> { typedef const T(&type)[N]; }; template <typename T, int N> struct deduce<const volatile T(&)[N]> { typedef const volatile T(&type)[N]; }; }}} #endif