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diff --git a/boost/spirit/home/x3/support/traits/transform_attribute.hpp b/boost/spirit/home/x3/support/traits/transform_attribute.hpp
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+++ b/boost/spirit/home/x3/support/traits/transform_attribute.hpp
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+/*=============================================================================
+    Copyright (c) 2001-2014 Joel de Guzman
+    Copyright (c) 2001-2012 Hartmut Kaiser
+    http://spirit.sourceforge.net/
+
+    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_SPIRIT_X3_ATTRIBUTE_TRANSFORM_JAN_8_2012_0721PM)
+#define BOOST_SPIRIT_X3_ATTRIBUTE_TRANSFORM_JAN_8_2012_0721PM
+
+#if defined(_MSC_VER)
+#pragma once
+#endif
+
+#include <boost/mpl/identity.hpp>
+
+namespace boost { namespace spirit { namespace x3 { namespace traits
+{
+    ///////////////////////////////////////////////////////////////////////////
+    //  transform_attribute
+    //
+    //  Sometimes the user needs to transform the attribute types for certain
+    //  attributes. This template can be used as a customization point, where
+    //  the user is able specify specific transformation rules for any attribute
+    //  type.
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename Exposed, typename Transformed, typename Tag
+      , typename Enable = void>
+    struct transform_attribute;
+
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename Tag, typename Transformed, typename Exposed>
+    typename transform_attribute<Exposed, Transformed, Tag>::type
+    pre_transform(Exposed& attr)
+    {
+        return transform_attribute<Exposed, Transformed, Tag>::pre(attr);
+    }
+
+    template <typename Tag, typename Transformed, typename Exposed>
+    typename transform_attribute<Exposed, Transformed, Tag>::type
+    pre_transform(Exposed const& attr)
+    {
+        return transform_attribute<Exposed const, Transformed, Tag>::pre(attr);
+    }
+}}}}
+
+#endif