branch for creating branch for fusion 2.1

[SVN r40237]

include/boost/fusion/support/is_sequence.hpp

@@ -0,0 +1,65 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 Joel de Guzman
+
+    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(FUSION_IS_SEQUENCE_05052005_1002)
+#define FUSION_IS_SEQUENCE_05052005_1002
+
+#include <boost/type_traits/is_base_of.hpp>
+#include <boost/fusion/support/sequence_base.hpp>
+#include <boost/fusion/support/tag_of.hpp>
+#include <boost/mpl/is_sequence.hpp>
+#include <boost/mpl/or.hpp>
+#include <boost/mpl/bool.hpp>
+
+namespace boost { namespace fusion
+{
+    // Special tags:
+    struct non_fusion_tag;
+    struct boost_tuple_tag; // boost::tuples::tuple tag
+    struct array_tag; // boost::array tag
+    struct mpl_sequence_tag; // mpl sequence tag
+    struct std_pair_tag; // std::pair tag
+
+    namespace extension
+    {
+        template <typename T>
+        struct is_sequence_impl
+        {
+            template <typename Sequence>
+            struct apply : is_base_of<sequence_root, Sequence> {};
+        };
+
+        template <>
+        struct is_sequence_impl<non_fusion_tag>
+        {
+            template <typename T>
+            struct apply : mpl::false_ {};
+        };
+
+        template <>
+        struct is_sequence_impl<boost_tuple_tag>;
+
+        template <>
+        struct is_sequence_impl<array_tag>;
+
+        template <>
+        struct is_sequence_impl<mpl_sequence_tag>;
+
+        template <>
+        struct is_sequence_impl<std_pair_tag>;
+    }
+
+    namespace traits
+    {
+        template <typename T>
+        struct is_sequence
+            : extension::is_sequence_impl<typename detail::tag_of<T>::type>::
+                template apply<T>
+        {};
+    }
+}}
+
+#endif