Chris@16: // Copyright 2004 The Trustees of Indiana University.
Chris@16: 
Chris@16: // Use, modification and distribution is subject to the Boost Software
Chris@16: // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: //  Authors: Douglas Gregor
Chris@16: //           Andrew Lumsdaine
Chris@16: 
Chris@16: //
Chris@16: // This file contains helps that enable concept-based overloading
Chris@16: // within the Boost Graph Library.
Chris@16: //
Chris@16: #ifndef BOOST_GRAPH_OVERLOADING_HPP
Chris@16: #define BOOST_GRAPH_OVERLOADING_HPP
Chris@16: 
Chris@16: #include <boost/type_traits/is_base_and_derived.hpp>
Chris@16: #include <boost/utility/enable_if.hpp>
Chris@16: 
Chris@16: namespace boost {  namespace graph { namespace detail {
Chris@16: 
Chris@16: struct no_parameter {};
Chris@16: 
Chris@16: } } } // end namespace boost::graph::detail
Chris@16: 
Chris@16: #ifndef BOOST_NO_SFINAE
Chris@16: 
Chris@16: #define BOOST_GRAPH_ENABLE_IF_MODELS(Graph, Tag, Type)               \
Chris@16:   typename enable_if_c<(is_base_and_derived<                         \
Chris@16:                           Tag,                                       \
Chris@16:                           typename graph_traits<Graph>::traversal_category>::value), \
Chris@16:                        Type>::type
Chris@16: 
Chris@16: #define BOOST_GRAPH_ENABLE_IF_MODELS_PARM(Graph, Tag)                   \
Chris@16:   , BOOST_GRAPH_ENABLE_IF_MODELS(Graph, Tag,                            \
Chris@16:                                  ::boost::graph::detail::no_parameter)  \
Chris@16:     = ::boost::graph::detail::no_parameter()
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16: #define BOOST_GRAPH_ENABLE_IF_MODELS(Graph, Tag, Type) Type
Chris@16: #define BOOST_GRAPH_ENABLE_IF_MODELS_PARM(Graph, Tag)
Chris@16: 
Chris@16: #endif // no SFINAE support
Chris@16: 
Chris@16: #endif // BOOST_GRAPH_OVERLOADING_HPP