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Editing: rebind_any.hpp
// Boost.TypeErasure library // // Copyright 2011 Steven Watanabe // // Distributed under 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) // // $Id$ #ifndef BOOST_TYPE_ERASURE_REBIND_ANY_HPP_INCLUDED #define BOOST_TYPE_ERASURE_REBIND_ANY_HPP_INCLUDED #include <boost/mpl/if.hpp> #include <boost/type_traits/remove_cv.hpp> #include <boost/type_traits/remove_reference.hpp> #include <boost/type_erasure/is_placeholder.hpp> #include <boost/type_erasure/concept_of.hpp> namespace boost { namespace type_erasure { #ifndef BOOST_TYPE_ERASURE_DOXYGEN template<class Concept, class T> class any; #endif /** * A metafunction that changes the @ref placeholder of * an @ref any. If @c T is not a placeholder, * returns @c T unchanged. This class is intended * to be used in @ref concept_interface to deduce * the argument types from the arguments of the concept. * * @pre Any must be a specialization of @ref any or a base * class of such a specialization. * * \code * rebind_any<any<Concept>, _a>::type -> any<Concept, _a> * rebind_any<any<Concept>, _b&>::type -> any<Concept, _b&> * rebind_any<any<Concept>, _c&&>::type -> any<Concept, _c&&> * rebind_any<any<Concept>, int>::type -> int * \endcode * * @see derived, as_param */ template<class Any, class T> struct rebind_any { #ifdef BOOST_TYPE_ERASURE_DOXYGEN typedef detail::unspecified type; #else typedef typename ::boost::mpl::if_< ::boost::type_erasure::is_placeholder< typename ::boost::remove_cv< typename ::boost::remove_reference<T>::type >::type >, ::boost::type_erasure::any< typename ::boost::type_erasure::concept_of<Any>::type, T >, T >::type type; #endif }; #ifndef BOOST_NO_CXX11_TEMPLATE_ALIASES template<class Any, class T> using rebind_any_t = typename ::boost::type_erasure::rebind_any<Any, T>::type; #endif } } #endif
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