boost/python/proxy.hpp

   1 // Copyright David Abrahams 2002.
   2 // Distributed under the Boost Software License, Version 1.0. (See
   3 // accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5 #ifndef PROXY_DWA2002615_HPP
   6 # define PROXY_DWA2002615_HPP
   7 # include <boost/python/detail/prefix.hpp>
   8 # include <boost/python/object_core.hpp>
   9 # include <boost/python/object_operators.hpp>
  10
  11 namespace boost { namespace python { namespace api {
  12
  13 template <class Policies>
  14 class proxy : public object_operators<proxy<Policies> >
  15 {
  16     typedef typename Policies::key_type key_type;
  17
  18 # if !defined(BOOST_MSVC) || BOOST_MSVC >= 1300
  19     typedef proxy const& assignment_self;
  20 # else
  21     typedef proxy assignment_self;
  22 # endif
  23  public:
  24     proxy(object const& target, key_type const& key);
  25     operator object() const;
  26
  27     // to support a[b] = c[d]
  28     proxy const& operator=(assignment_self) const;
  29
  30     template <class T>
  31     inline proxy const& operator=(T const& rhs) const
  32     {
  33         Policies::set(m_target, m_key, object(rhs));
  34         return *this;
  35     }
  36
  37  public: // implementation detail
  38     void del() const;
  39
  40  private:
  41     object m_target;
  42     key_type m_key;
  43 };
  44
  45
  46 template <class T>
  47 inline void del(proxy<T> const& x)
  48 {
  49     x.del();
  50 }
  51
  52 //
  53 // implementation
  54 //
  55
  56 template <class Policies>
  57 inline proxy<Policies>::proxy(object const& target, key_type const& key)
  58     : m_target(target), m_key(key)
  59 {}
  60
  61 template <class Policies>
  62 inline proxy<Policies>::operator object() const
  63 {
  64     return Policies::get(m_target, m_key);
  65 }
  66
  67 // to support a[b] = c[d]
  68 template <class Policies>
  69 inline proxy<Policies> const& proxy<Policies>::operator=(typename proxy::assignment_self rhs) const
  70 {
  71     return *this = python::object(rhs);
  72 }
  73
  74 # define BOOST_PYTHON_PROXY_INPLACE(op)                                         \
  75 template <class Policies, class R>                                              \
  76 proxy<Policies> const& operator op(proxy<Policies> const& lhs, R const& rhs)    \
  77 {                                                                               \
  78     object old(lhs);                                                            \
  79     return lhs = (old op rhs);                                                  \
  80 }
  81 BOOST_PYTHON_PROXY_INPLACE(+=)
  82 BOOST_PYTHON_PROXY_INPLACE(-=)
  83 BOOST_PYTHON_PROXY_INPLACE(*=)
  84 BOOST_PYTHON_PROXY_INPLACE(/=)
  85 BOOST_PYTHON_PROXY_INPLACE(%=)
  86 BOOST_PYTHON_PROXY_INPLACE(<<=)
  87 BOOST_PYTHON_PROXY_INPLACE(>>=)
  88 BOOST_PYTHON_PROXY_INPLACE(&=)
  89 BOOST_PYTHON_PROXY_INPLACE(^=)
  90 BOOST_PYTHON_PROXY_INPLACE(|=)
  91 # undef BOOST_PYTHON_PROXY_INPLACE
  92
  93 template <class Policies>
  94 inline void proxy<Policies>::del() const
  95 {
  96     Policies::del(m_target, m_key);
  97 }
  98
  99 }}} // namespace boost::python::api
 100
 101 #endif // PROXY_DWA2002615_HPP