From 0df5ebf0fad2dcac06a85cbdb94d7a310328a2e9 Mon Sep 17 00:00:00 2001
From: Dave Abrahams <dave@boostpro.com>
Date: Wed, 18 Dec 2002 21:11:16 +0000
Subject: [PATCH] Fix to allow accessing enums as data members

[SVN r16656]
---
 include/boost/python/data_members.hpp | 40 +++++++++++++++++----------
 test/enum.cpp                         | 10 +++++++
 test/enum.py                          |  6 ++++
 3 files changed, 42 insertions(+), 14 deletions(-)

diff --git a/include/boost/python/data_members.hpp b/include/boost/python/data_members.hpp
index a8ff3871..9c4574b4 100644
--- a/include/boost/python/data_members.hpp
+++ b/include/boost/python/data_members.hpp
@@ -6,18 +6,25 @@
 #ifndef DATA_MEMBERS_DWA2002328_HPP
 # define DATA_MEMBERS_DWA2002328_HPP
 
-# include <boost/python/detail/config.hpp>
-# include <boost/python/detail/wrap_python.hpp>
-# include <boost/type_traits/transform_traits.hpp>
-# include <boost/type_traits/add_const.hpp>
-# include <boost/type_traits/add_reference.hpp>
 # include <boost/python/return_value_policy.hpp>
 # include <boost/python/return_by_value.hpp>
 # include <boost/python/return_internal_reference.hpp>
-# include <boost/python/object/function_object.hpp>
 # include <boost/python/arg_from_python.hpp>
+
+# include <boost/python/object/function_object.hpp>
+
 # include <boost/python/converter/builtin_converters.hpp>
+
+# include <boost/python/detail/indirect_traits.hpp>
+# include <boost/python/detail/config.hpp>
+# include <boost/python/detail/wrap_python.hpp>
+
+# include <boost/type_traits/transform_traits.hpp>
+# include <boost/type_traits/add_const.hpp>
+# include <boost/type_traits/add_reference.hpp>
+
 # include <boost/mpl/if.hpp>
+
 # include <boost/bind.hpp>
 
 namespace boost { namespace python { 
@@ -71,16 +78,21 @@ namespace detail
   // and get the right result.
   template <class T>
   struct default_getter_policy
-      : mpl::if_c<
-        to_python_value<
-          typename add_reference<
-              typename add_const<T>::type
-          >::type
-        >::uses_registry
+  {
+      typedef typename add_reference<
+          typename add_const<T>::type
+      >::type t_cref;
+
+      BOOST_STATIC_CONSTANT(
+          bool, by_ref = to_python_value<t_cref>::uses_registry
+                        && is_reference_to_class<t_cref>::value);
+
+      typedef typename mpl::if_c<
+        by_ref
         , return_internal_reference<>
         , return_value_policy<return_by_value>
-    >
-  {};
+      >::type type;
+  };
 }
 
 template <class C, class D>
diff --git a/test/enum.cpp b/test/enum.cpp
index fb1439c7..09a916c3 100644
--- a/test/enum.cpp
+++ b/test/enum.cpp
@@ -6,6 +6,7 @@
 #include <boost/python/enum.hpp>
 #include <boost/python/def.hpp>
 #include <boost/python/module.hpp>
+#include <boost/python/class.hpp>
 
 using namespace boost::python;
 
@@ -13,6 +14,11 @@ enum color { red = 1, green = 2, blue = 4 };
 
 color identity_(color x) { return x; }
 
+struct colorized {
+    colorized() : x(red) {}
+    color x;
+};
+
 BOOST_PYTHON_MODULE(enum_ext)
 {
     enum_<color>("color")
@@ -23,6 +29,10 @@ BOOST_PYTHON_MODULE(enum_ext)
         ;
     
     def("identity", identity_);
+
+    class_<colorized>("colorized")
+        .def_readwrite("x", &colorized::x)
+        ;
 }
 
 #include "module_tail.cpp"
diff --git a/test/enum.py b/test/enum.py
index 00484670..e99e401e 100644
--- a/test/enum.py
+++ b/test/enum.py
@@ -37,6 +37,12 @@ enum_ext.color.blue
 ... except TypeError: pass
 ... else: print 'expected a TypeError'
 
+>>> c = colorized()
+>>> c.x
+enum_ext.color.red
+>>> c.x = green
+>>> c.x
+enum_ext.color.green
 '''
 
 def run(args = None):