baking segmented Fusion

[SVN r73854]

include/boost/fusion/iterator/detail/segment_sequence.hpp

@@ -0,0 +1,71 @@
+/*=============================================================================
+    Copyright (c) 2011 Eric Niebler
+
+    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_SEGMENTED_SEQUENCE_HPP_INCLUDED)
+#define BOOST_FUSION_SEGMENTED_SEQUENCE_HPP_INCLUDED
+
+#include <boost/mpl/bool.hpp>
+#include <boost/type_traits/remove_reference.hpp>
+#include <boost/fusion/support/tag_of.hpp>
+#include <boost/fusion/sequence/intrinsic_fwd.hpp>
+
+namespace boost { namespace fusion { namespace detail
+{
+    struct segment_sequence_tag {};
+
+    // Here, Sequence is a sequence of ranges (which may or may not be
+    // segmented).
+    template<typename Sequence>
+    struct segment_sequence
+        : sequence_base<segment_sequence<Sequence> >
+    {
+        typedef fusion_sequence_tag tag;
+        typedef segment_sequence_tag fusion_tag;
+        typedef typename Sequence::is_view is_view;
+        typedef typename Sequence::category category;
+        typedef Sequence sequence_type;
+        sequence_type sequence;
+
+        explicit segment_sequence(Sequence const & seq)
+            : sequence(seq)
+        {}
+    };
+}
+
+namespace extension
+{
+    template<typename Tag>
+    struct is_segmented_impl;
+
+    template<>
+    struct is_segmented_impl<detail::segment_sequence_tag>
+    {
+        template<typename Sequence>
+        struct apply
+            : mpl::true_
+        {};
+    };
+
+    template<typename Tag>
+    struct segments_impl;
+
+    template<>
+    struct segments_impl<detail::segment_sequence_tag>
+    {
+        template<typename Sequence>
+        struct apply
+        {
+            typedef typename Sequence::sequence_type type;
+
+            static type call(Sequence & seq)
+            {
+                return seq.sequence;
+            }
+        };
+    };
+}}}
+
+#endif