| // 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_PLACEHOLDER_OF_HPP_INCLUDED |
| #define BOOST_TYPE_ERASURE_PLACEHOLDER_OF_HPP_INCLUDED |
| |
| namespace boost { |
| namespace type_erasure { |
| |
| template<class Concept, class T> |
| class any; |
| |
| template<class Concept, class T> |
| class param; |
| |
| /** |
| * A metafunction returning the (const/reference qualified) placeholder |
| * corresponding to an @ref any. It will also work for all bases |
| * of @ref any, so it can be applied to the @c Base |
| * parameter of @ref concept_interface. |
| */ |
| template<class T> |
| struct placeholder_of |
| { |
| #ifdef BOOST_TYPE_ERASURE_DOXYGEN |
| typedef detail::unspecified type; |
| #else |
| typedef typename ::boost::type_erasure::placeholder_of< |
| typename T::_boost_type_erasure_derived_type |
| >::type type; |
| #endif |
| }; |
| |
| /** INTERNAL ONLY */ |
| template<class Concept, class T> |
| struct placeholder_of< ::boost::type_erasure::any<Concept, T> > |
| { |
| typedef T type; |
| }; |
| |
| /** INTERNAL ONLY */ |
| template<class Concept, class T> |
| struct placeholder_of< ::boost::type_erasure::param<Concept, T> > |
| { |
| typedef T type; |
| }; |
| |
| } |
| } |
| |
| #endif |