From b905aa11af1200fe945c70848d6d7162da22657a Mon Sep 17 00:00:00 2001
From: Joel de Guzman <djowel@gmail.com>
Date: Sat, 8 Oct 2011 03:47:16 +0000
Subject: [PATCH] Added adapter for std::tuple (only for implementations using
 variadic templates)

[SVN r74788]
---
 include/boost/fusion/sequence/intrinsic/at.hpp | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/include/boost/fusion/sequence/intrinsic/at.hpp b/include/boost/fusion/sequence/intrinsic/at.hpp
index 8c225857..92da7bbd 100644
--- a/include/boost/fusion/sequence/intrinsic/at.hpp
+++ b/include/boost/fusion/sequence/intrinsic/at.hpp
@@ -1,7 +1,7 @@
 /*=============================================================================
     Copyright (c) 2001-2011 Joel de Guzman
 
-    Distributed under the Boost Software License, Version 1.0. (See accompanying 
+    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_AT_05042005_0722)
@@ -21,6 +21,7 @@ namespace boost { namespace fusion
     struct boost_array_tag; // boost::array tag
     struct mpl_sequence_tag; // mpl sequence tag
     struct std_pair_tag; // std::pair tag
+    struct std_tuple_tag; // std::tuple tag
 
     namespace extension
     {
@@ -49,12 +50,15 @@ namespace boost { namespace fusion
 
         template <>
         struct at_impl<std_pair_tag>;
+
+        template <>
+        struct at_impl<std_tuple_tag>;
     }
 
     namespace result_of
     {
         template <typename Sequence, typename N>
-        struct at 
+        struct at
             : extension::at_impl<typename detail::tag_of<Sequence>::type>::
                 template apply<Sequence, N>
         {};
@@ -67,7 +71,7 @@ namespace boost { namespace fusion
 
 
     template <typename N, typename Sequence>
-    inline typename 
+    inline typename
         lazy_disable_if<
             is_const<Sequence>
           , result_of::at<Sequence, N>
@@ -85,7 +89,7 @@ namespace boost { namespace fusion
     }
 
     template <int N, typename Sequence>
-    inline typename 
+    inline typename
         lazy_disable_if<
             is_const<Sequence>
           , result_of::at_c<Sequence, N>