Initial move from Spirit CVS

[SVN r34896]

include/boost/fusion/support/is_sequence.hpp

@@ -0,0 +1,51 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 Joel de Guzman
+
+    Use, modification and distribution is subject to 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_and_derived.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
+{
+    struct non_fusion_tag;
+
+    namespace extension
+    {
+        template<typename T>
+        struct is_sequence_impl
+            : is_base_and_derived<sequence_root, T>
+        {
+            template<typename Sequence>
+            struct apply 
+                : is_base_and_derived<sequence_root, Sequence>
+            {};
+        };
+
+        template<>
+        struct is_sequence_impl<non_fusion_tag>
+        {
+            template<typename T>
+            struct apply : mpl::false_ {};
+        };
+    }
+
+    namespace traits
+    {
+        template <typename T>
+        struct is_sequence
+            : extension::is_sequence_impl<typename detail::tag_of<T>::type>::template apply<T>
+        {};
+    }
+}}
+
+#endif