branch for creating branch for fusion 2.1

[SVN r40237]

include/boost/fusion/container/deque/detail/keyed_element.hpp

@@ -0,0 +1,111 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 Joel de Guzman
+    Copyright (c) 2005-2006 Dan Marsden
+
+    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)
+==============================================================================*/
+#if !defined(BOOST_FUSION_DEQUE_DETAIL_KEYED_ELEMENT_26112006_1330)
+#define BOOST_FUSION_DEQUE_DETAIL_KEYED_ELEMENT_26112006_1330
+
+#include <boost/type_traits/add_reference.hpp>
+#include <boost/type_traits/add_const.hpp>
+
+#include <boost/fusion/iterator/deref.hpp>
+#include <boost/fusion/iterator/next.hpp>
+
+namespace boost { namespace fusion {
+
+    struct fusion_sequence_tag;
+
+namespace detail {
+
+    struct nil_keyed_element
+    {
+        typedef fusion_sequence_tag tag;
+        void get();
+
+        template<typename It>
+        static nil_keyed_element 
+        from_iterator(It const&)
+        {
+            return nil_keyed_element();
+        }
+    };
+
+    template<typename Key, typename Value, typename Rest>
+    struct keyed_element
+        : Rest
+    {
+        typedef Rest base;
+        typedef fusion_sequence_tag tag;
+        using Rest::get;
+
+        template<typename It>
+        static keyed_element
+        from_iterator(It const& it)
+        {
+            return keyed_element(
+                *it, base::from_iterator(fusion::next(it)));
+        }
+
+        template<typename U, typename Rst>
+        keyed_element(keyed_element<Key, U, Rst> const& rhs)
+            : Rest(rhs.get_base()), value_(rhs.value_)
+        {}
+
+        Rest const get_base() const
+        {
+            return *this;
+        }
+
+        typename add_reference<typename add_const<Value>::type>::type get(Key) const
+        {
+            return value_;
+        }
+
+        typename add_reference<Value>::type get(Key)
+        {
+            return value_;
+        }
+
+        keyed_element(typename add_reference<typename add_const<Value>::type>::type value, Rest const& rest)
+            : Rest(rest), value_(value)
+        {}
+
+        keyed_element()
+            : Rest(), value_()
+        {}
+
+        template<typename U, typename Rst>
+        keyed_element& operator=(keyed_element<Key, U, Rst> const& rhs)
+        {
+            base::operator=(static_cast<Rst const&>(rhs)); // cast for msvc-7.1
+            value_ = rhs.value_;
+            return *this;
+        }
+
+        keyed_element& operator=(keyed_element const& rhs)
+        {
+            base::operator=(rhs);
+            value_ = rhs.value_;
+            return *this;
+        }
+
+        Value value_;
+    };
+
+    template<typename Elem, typename Key>
+    struct keyed_element_value_at
+        : keyed_element_value_at<typename Elem::base, Key>
+    {};
+
+    template<typename Key, typename Value, typename Rest>
+    struct keyed_element_value_at<keyed_element<Key, Value, Rest>, Key>
+    {
+        typedef Value type;
+    };
+
+}}}
+
+#endif