// 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 BACK_REFERENCE_DWA2002510_HPP

 # define BACK_REFERENCE_DWA2002510_HPP

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

 # include <boost/python/object_fwd.hpp>

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

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

 namespace boost { namespace python { 

 template <class T>

 struct back_reference

 {

  private: // types

     typedef typename detail::dependent<object,T>::type source_t;

  public:

     typedef T type;

     back_reference(PyObject*, T);

     source_t const& source() const;

     T get() const;

  private:

     source_t m_source;

     T m_value;

 };

 # ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

 template<typename T>

 class is_back_reference

 {

  public:

     BOOST_STATIC_CONSTANT(bool, value = false); 

 };

 template<typename T>

 class is_back_reference<back_reference<T> >

 {

  public:

     BOOST_STATIC_CONSTANT(bool, value = true);

 };

 # else // no partial specialization

 }} // namespace boost::python

 #include <boost/type.hpp>

 namespace boost { namespace python {

 namespace detail

 {

   typedef char (&yes_back_reference_t)[1];

   typedef char (&no_back_reference_t)[2];

   no_back_reference_t is_back_reference_test(...);

   template<typename T>

   yes_back_reference_t is_back_reference_test(boost::type< back_reference<T> >);

 }

 template<typename T>

 class is_back_reference

 {

  public:

     BOOST_STATIC_CONSTANT(

         bool, value = (

             sizeof(detail::is_back_reference_test(boost::type<T>()))

             == sizeof(detail::yes_back_reference_t)));

 };

 # endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

 //

 // implementations

 //

 template <class T>

 back_reference<T>::back_reference(PyObject* p, T x)

     : m_source(detail::borrowed_reference(p))

       , m_value(x)

 {

 }

 template <class T>

 typename back_reference<T>::source_t const& back_reference<T>::source() const

 {

     return m_source;

 }

 template <class T>

 T back_reference<T>::get() const

 {

     return m_value;

 }

 }} // namespace boost::python

 #endif // BACK_REFERENCE_DWA2002510_HPP