[identity_view] Added boost::fusion::identity_view

include/boost/fusion/view/identity_view/identity_view.hpp

@@ -10,41 +10,18 @@
 #include <boost/fusion/support/config.hpp>
 #include <boost/fusion/view/transform_view.hpp>
 #include <boost/functional/identity.hpp>
-#include <boost/utility/result_of.hpp>
 
-namespace boost { namespace fusion {
-    namespace detail {
-        struct identity : boost::identity
-        {
-        };
-    }
-}}
-
-namespace boost {
-    template<typename T>
-    struct result_of<fusion::detail::identity(T)>
-    {
-        typedef T type;
-    };
-}
-
-#ifdef _MSC_VER
-#  pragma warning(push)
-#  pragma warning(disable: 4512) // assignment operator could not be generated.
-#endif
 namespace boost { namespace fusion {
     template<typename Sequence> struct identity_view 
-        : transform_view<Sequence, detail::identity>
+        : transform_view<Sequence, boost::identity>
     {
-        typedef transform_view<Sequence, detail::identity> base_type;
+        typedef transform_view<Sequence, boost::identity> base_type;
 
         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
         identity_view(Sequence& in_seq)
-            : base_type(in_seq, detail::identity()) {}
+            : base_type(in_seq, boost::identity()) {}
     };
+
 }}
-#ifdef _MSC_VER
-#  pragma warning(pop)
-#endif
 
 #endif