1 | // Copyright David Abrahams 2002. |
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2 | // Distributed under the Boost Software License, Version 1.0. (See |
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3 | // accompanying file LICENSE_1_0.txt or copy at |
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4 | // http://www.boost.org/LICENSE_1_0.txt) |
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5 | #ifndef BASES_DWA2002321_HPP |
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6 | # define BASES_DWA2002321_HPP |
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7 | |
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8 | # include <boost/python/detail/prefix.hpp> |
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9 | # include <boost/type_traits/object_traits.hpp> |
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10 | # include <boost/python/detail/type_list.hpp> |
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11 | # include <boost/mpl/if.hpp> |
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12 | # include <boost/mpl/bool.hpp> |
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13 | # include <boost/preprocessor/enum_params_with_a_default.hpp> |
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14 | # include <boost/preprocessor/enum_params.hpp> |
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15 | |
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16 | namespace boost { namespace python { |
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17 | |
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18 | # define BOOST_PYTHON_BASE_PARAMS BOOST_PP_ENUM_PARAMS_Z(1, BOOST_PYTHON_MAX_BASES, Base) |
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19 | |
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20 | // A type list for specifying bases |
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21 | template < BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(BOOST_PYTHON_MAX_BASES, typename Base, mpl::void_) > |
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22 | struct bases : detail::type_list< BOOST_PYTHON_BASE_PARAMS >::type |
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23 | {}; |
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24 | |
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25 | namespace detail |
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26 | { |
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27 | # ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
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28 | template <class T> struct specifies_bases |
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29 | : mpl::false_ |
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30 | { |
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31 | }; |
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32 | |
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33 | template < BOOST_PP_ENUM_PARAMS_Z(1, BOOST_PYTHON_MAX_BASES, class Base) > |
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34 | struct specifies_bases< bases< BOOST_PYTHON_BASE_PARAMS > > |
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35 | : mpl::true_ |
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36 | { |
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37 | }; |
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38 | # else |
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39 | template < BOOST_PP_ENUM_PARAMS(BOOST_PYTHON_MAX_BASES, class Base) > |
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40 | static char is_bases_helper(bases< BOOST_PYTHON_BASE_PARAMS > const&); |
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41 | |
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42 | static char (& is_bases_helper(...) )[256]; |
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43 | |
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44 | template <class T> |
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45 | struct specifies_bases |
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46 | { |
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47 | private: |
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48 | static typename add_reference<T>::type make(); |
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49 | BOOST_STATIC_CONSTANT(bool, non_ref = !is_reference<T>::value); |
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50 | public: |
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51 | BOOST_STATIC_CONSTANT(bool, value = non_ref & (sizeof(is_bases_helper(make())) == 1)); |
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52 | typedef mpl::bool_<value> type; |
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53 | }; |
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54 | # endif |
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55 | template <class T, class Prev = bases<> > |
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56 | struct select_bases |
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57 | : mpl::if_< |
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58 | specifies_bases<T> |
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59 | , T |
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60 | , Prev |
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61 | > |
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62 | { |
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63 | }; |
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64 | } |
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65 | # undef BOOST_PYTHON_BASE_PARAMS |
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66 | }} // namespace boost::python |
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67 | |
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68 | #endif // BASES_DWA2002321_HPP |
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