// Copyright David Abrahams 2002.

// 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)

#ifndef BASES_DWA2002321_HPP

# define BASES_DWA2002321_HPP

# include <boost/python/detail/prefix.hpp>

# include <boost/type_traits/object_traits.hpp>

# include <boost/python/detail/type_list.hpp>

# include <boost/mpl/if.hpp>

# include <boost/mpl/bool.hpp>

# include <boost/preprocessor/enum_params_with_a_default.hpp>

# include <boost/preprocessor/enum_params.hpp>

namespace boost { namespace python { 

# define BOOST_PYTHON_BASE_PARAMS BOOST_PP_ENUM_PARAMS_Z(1, BOOST_PYTHON_MAX_BASES, Base)

  // A type list for specifying bases

  template < BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(BOOST_PYTHON_MAX_BASES, typename Base, mpl::void_) >

  struct bases : detail::type_list< BOOST_PYTHON_BASE_PARAMS >::type

  {};

  namespace detail

  {

# ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

    template <class T> struct specifies_bases

        : mpl::false_

    {

    };

    template < BOOST_PP_ENUM_PARAMS_Z(1, BOOST_PYTHON_MAX_BASES, class Base) >

    struct specifies_bases< bases< BOOST_PYTHON_BASE_PARAMS > >

        : mpl::true_

    {

    };

# else

    template < BOOST_PP_ENUM_PARAMS(BOOST_PYTHON_MAX_BASES, class Base) >

    static char is_bases_helper(bases< BOOST_PYTHON_BASE_PARAMS > const&);

    static char (& is_bases_helper(...) )[256];

    template <class T>

    struct specifies_bases

    {

     private:

        static typename add_reference<T>::type make();

        BOOST_STATIC_CONSTANT(bool, non_ref = !is_reference<T>::value);

     public:

        BOOST_STATIC_CONSTANT(bool, value = non_ref & (sizeof(is_bases_helper(make())) == 1));

        typedef mpl::bool_<value> type;

    };

# endif

    template <class T, class Prev = bases<> >

    struct select_bases

        : mpl::if_<

                specifies_bases<T>

                , T

                , Prev

          >

    {

    };

  }

# undef BOOST_PYTHON_BASE_PARAMS

}} // namespace boost::python

#endif // BASES_DWA2002321_HPP