| // 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 |