Added boost header

test/external/boost/proto/functional/fusion/at.hpp

@@ -0,0 +1,56 @@
+///////////////////////////////////////////////////////////////////////////////
+/// \file at.hpp
+/// Proto callables Fusion at
+//
+//  Copyright 2010 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)
+
+#ifndef BOOST_PROTO_FUNCTIONAL_FUSION_AT_HPP_EAN_11_27_2010
+#define BOOST_PROTO_FUNCTIONAL_FUSION_AT_HPP_EAN_11_27_2010
+
+#include <boost/type_traits/add_const.hpp>
+#include <boost/type_traits/remove_const.hpp>
+#include <boost/type_traits/remove_reference.hpp>
+#include <boost/fusion/include/at.hpp>
+#include <boost/proto/proto_fwd.hpp>
+
+namespace boost { namespace proto { namespace functional
+{
+    /// \brief A PolymorphicFunctionObject type that invokes the
+    /// \c fusion::at() accessor on its argument.
+    ///
+    /// A PolymorphicFunctionObject type that invokes the
+    /// \c fusion::at() accessor on its argument.
+    struct at
+    {
+        BOOST_PROTO_CALLABLE()
+
+        template<typename Sig>
+        struct result;
+
+        template<typename This, typename Seq, typename N>
+        struct result<This(Seq, N)>
+          : fusion::result_of::at<
+                typename boost::remove_reference<Seq>::type
+              , typename boost::remove_const<typename boost::remove_reference<N>::type>::type
+            >
+        {};
+
+        template<typename Seq, typename N>
+        typename fusion::result_of::at<Seq, N>::type
+        operator ()(Seq &seq, N const & BOOST_PROTO_DISABLE_IF_IS_CONST(Seq)) const
+        {
+            return fusion::at<N>(seq);
+        }
+
+        template<typename Seq, typename N>
+        typename fusion::result_of::at<Seq const, N>::type
+        operator ()(Seq const &seq, N const &) const
+        {
+            return fusion::at<N>(seq);
+        }
+    };
+}}}
+
+#endif