sl@0: // Copyright David Abrahams 2002.
sl@0: // Distributed under the Boost Software License, Version 1.0. (See
sl@0: // accompanying file LICENSE_1_0.txt or copy at
sl@0: // http://www.boost.org/LICENSE_1_0.txt)
sl@0: #ifndef BASES_DWA2002321_HPP
sl@0: # define BASES_DWA2002321_HPP
sl@0: 
sl@0: # include <boost/python/detail/prefix.hpp>
sl@0: # include <boost/type_traits/object_traits.hpp>
sl@0: # include <boost/python/detail/type_list.hpp>
sl@0: # include <boost/mpl/if.hpp>
sl@0: # include <boost/mpl/bool.hpp>
sl@0: # include <boost/preprocessor/enum_params_with_a_default.hpp>
sl@0: # include <boost/preprocessor/enum_params.hpp>
sl@0: 
sl@0: namespace boost { namespace python { 
sl@0: 
sl@0: # define BOOST_PYTHON_BASE_PARAMS BOOST_PP_ENUM_PARAMS_Z(1, BOOST_PYTHON_MAX_BASES, Base)
sl@0: 
sl@0:   // A type list for specifying bases
sl@0:   template < BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(BOOST_PYTHON_MAX_BASES, typename Base, mpl::void_) >
sl@0:   struct bases : detail::type_list< BOOST_PYTHON_BASE_PARAMS >::type
sl@0:   {};
sl@0: 
sl@0:   namespace detail
sl@0:   {
sl@0: # ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
sl@0:     template <class T> struct specifies_bases
sl@0:         : mpl::false_
sl@0:     {
sl@0:     };
sl@0:     
sl@0:     template < BOOST_PP_ENUM_PARAMS_Z(1, BOOST_PYTHON_MAX_BASES, class Base) >
sl@0:     struct specifies_bases< bases< BOOST_PYTHON_BASE_PARAMS > >
sl@0:         : mpl::true_
sl@0:     {
sl@0:     };
sl@0: # else
sl@0:     template < BOOST_PP_ENUM_PARAMS(BOOST_PYTHON_MAX_BASES, class Base) >
sl@0:     static char is_bases_helper(bases< BOOST_PYTHON_BASE_PARAMS > const&);
sl@0:     
sl@0:     static char (& is_bases_helper(...) )[256];
sl@0: 
sl@0:     template <class T>
sl@0:     struct specifies_bases
sl@0:     {
sl@0:      private:
sl@0:         static typename add_reference<T>::type make();
sl@0:         BOOST_STATIC_CONSTANT(bool, non_ref = !is_reference<T>::value);
sl@0:      public:
sl@0:         BOOST_STATIC_CONSTANT(bool, value = non_ref & (sizeof(is_bases_helper(make())) == 1));
sl@0:         typedef mpl::bool_<value> type;
sl@0:     };
sl@0: # endif
sl@0:     template <class T, class Prev = bases<> >
sl@0:     struct select_bases
sl@0:         : mpl::if_<
sl@0:                 specifies_bases<T>
sl@0:                 , T
sl@0:                 , Prev
sl@0:           >
sl@0:     {
sl@0:     };
sl@0:   }
sl@0: # undef BOOST_PYTHON_BASE_PARAMS
sl@0: }} // namespace boost::python
sl@0: 
sl@0: #endif // BASES_DWA2002321_HPP