Fusion: added nview and friends

[SVN r56376]

include/boost/fusion/view/nview/detail/deref_impl.hpp

@@ -0,0 +1,47 @@
+/*=============================================================================
+    Copyright (c) 2009 Hartmut Kaiser
+
+    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_NVIEW_DEREF_IMPL_SEP_24_2009_0818AM)
+#define BOOST_FUSION_NVIEW_DEREF_IMPL_SEP_24_2009_0818AM
+
+#include <boost/fusion/iterator/deref.hpp>
+#include <boost/fusion/container/vector.hpp>
+
+namespace boost { namespace fusion
+{
+    struct nview_iterator_tag;
+
+    namespace extension
+    {
+        template<typename Tag>
+        struct deref_impl;
+
+        template<>
+        struct deref_impl<nview_iterator_tag>
+        {
+            template<typename Iterator>
+            struct apply
+            {
+                typedef typename Iterator::first_type first_type;
+                typedef typename Iterator::sequence_type sequence_type;
+
+                typedef typename result_of::deref<first_type>::type index;
+                typedef typename result_of::at<sequence_type, index>::type type;
+
+                static type call(Iterator const& i)
+                {
+                    return at<index>(i.seq);
+                }
+            };
+        };
+
+    }
+
+}}
+
+#endif
+