1 files changed, 82 insertions, 0 deletions
diff --git a/boost/fusion/support/tag_of.hpp b/boost/fusion/support/tag_of.hpp
new file mode 100644
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+++ b/boost/fusion/support/tag_of.hpp
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+/*=============================================================================
+    Copyright (c) 2001-2011 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_TAG_OF_09232005_0845)
+#define FUSION_TAG_OF_09232005_0845
+
+#include <boost/utility/enable_if.hpp>
+#include <boost/type_traits/remove_const.hpp>
+#include <boost/fusion/support/tag_of_fwd.hpp>
+#include <boost/fusion/support/detail/is_mpl_sequence.hpp>
+#include <boost/mpl/has_xxx.hpp>
+#include <boost/mpl/identity.hpp>
+#include <boost/mpl/assert.hpp>
+#include <boost/mpl/bool.hpp>
+#include <boost/mpl/if.hpp>
+#include <boost/config/no_tr1/utility.hpp>
+
+namespace boost
+{
+    template <typename T, std::size_t N>
+    class array; // forward
+
+    namespace tuples
+    {
+        struct null_type;
+
+        template <
+            class T0, class T1, class T2, class T3, class T4,
+            class T5, class T6, class T7, class T8, class T9
+        >
+        class tuple;
+
+        template <class Head, class Tail>
+        struct cons;
+    }
+}
+
+namespace boost { namespace fusion
+{
+    struct non_fusion_tag;
+    struct mpl_sequence_tag;
+
+    namespace detail
+    {
+        BOOST_MPL_HAS_XXX_TRAIT_DEF(fusion_tag)
+
+        template <typename Sequence, typename Active>
+        struct tag_of_impl
+          : mpl::if_<fusion::detail::is_mpl_sequence<Sequence>,
+              mpl::identity<mpl_sequence_tag>,
+              mpl::identity<non_fusion_tag> >::type
+        {};
+
+        template <typename Sequence>
+        struct tag_of_impl<
+            Sequence
+          , typename boost::enable_if<detail::has_fusion_tag<Sequence> >::type>
+        {
+            typedef typename Sequence::fusion_tag type;
+        };
+    }
+
+    namespace traits
+    {
+        template <typename Sequence, typename Active>
+        struct tag_of
+            : boost::fusion::detail::tag_of_impl<Sequence, Active>
+        {};
+    }
+
+    namespace detail
+    {
+        template<typename T>
+        struct tag_of
+            : traits::tag_of<typename remove_const<T>::type>
+        {};
+    }
+}}
+#endif