This commit was manufactured by cvs2svn to create branch

'unlabeled-1.7.2'.

[SVN r13266]

include/boost/python/object/class_converters.hpp

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+// Copyright David Abrahams 2002. Permission to copy, use,
+// modify, sell and distribute this software is granted provided this
+// copyright notice appears in all copies. This software is provided
+// "as is" without express or implied warranty, and with no claim as
+// to its suitability for any purpose.
+#ifndef CLASS_CONVERTERS_DWA2002119_HPP
+# define CLASS_CONVERTERS_DWA2002119_HPP
+
+# include <boost/python/object/class_wrapper.hpp>
+# include <boost/mpl/for_each.hpp>
+# include <boost/python/reference.hpp>
+# include <boost/python/converter/registry.hpp>
+# include <boost/python/object/find_instance.hpp>
+# include <boost/python/object/inheritance.hpp>
+
+namespace boost { namespace python { namespace objects { 
+
+//////////////////////////////////////////////////////////////////////
+//
+// register_base_of<T> -
+//      A BinaryMetaFunction object which registers a single base
+//      class of T, and the corresponding cast(s)
+//
+
+
+// register_downcast/do_nothing -
+//      Helpers for register_base_of<> which take care of registering
+//      down-casts
+template <class Base, class Derived>
+struct register_downcast
+{
+    static void execute()
+    {
+        register_conversion<Base, Derived>(true);
+    }
+};
+
+struct do_nothing
+{
+    static void execute() { }
+};
+
+// Here's where the real work gets done:
+template <class Derived>
+struct register_base_of
+{
+    // Ignored is needed because mpl::for_each is still actually
+    // accumulate. We're not using any state so it just sits there.
+    template <class Ignored, class Base>
+    struct apply
+    {
+        typedef void type; // 'type' needs to be defined for the same reasons
+
+        // Here's the runtime part:
+        static void execute()
+        {
+            // Register the Base class
+            register_dynamic_id<Base>();
+            // Register the up-cast
+            register_conversion<Derived,Base>(false);
+
+            // Register the down-cast, if appropriate.
+            mpl::select_type<
+                is_polymorphic<Base>::value
+                , register_downcast<Base,Derived>
+                , do_nothing
+                >::type::execute();
+        }
+    };
+};
+
+
+// Brings into existence all converters associated with a class Bases
+// is expected to be an mpl sequence of base types.
+template <class Derived, class Bases>
+inline void register_class_from_python(Derived* = 0, Bases* = 0)
+{
+    // cause the static registration to be instantiated. Can't just
+    // cast it to void on all compilers; some will skip its
+    // initialization.
+    void const* ignored = &instance_finder<Derived>::registration;
+    (void)ignored;
+    
+    // register all up/downcasts here
+    register_dynamic_id<Derived>();
+
+    // register each base in the sequence
+    mpl::for_each<Bases, void, register_base_of<Derived> >::execute();
+}
+
+}}} // namespace boost::python::object
+
+#endif // CLASS_CONVERTERS_DWA2002119_HPP