Added BOOST_PP_EXPAND()

[SVN r12362]

include/boost/preprocessor/expand.hpp

@@ -0,0 +1,24 @@
+#ifndef BOOST_PREPROCESSOR_EXPAND_HPP
+#define BOOST_PREPROCESSOR_EXPAND_HPP
+
+// Copyright (C) 2001
+// Housemarque Oy
+// http://www.housemarque.com
+//
+// Permission to copy, use, modify, sell and distribute this software is
+// granted provided this copyright notice appears in all copies. This
+// software is provided "as is" without express or implied warranty, and
+// with no claim as to its suitability for any purpose.
+
+// See http://www.boost.org for most recent version.
+
+/*! \file
+
+<a href="../../../../boost/preprocessor/expand.hpp">Click here to see the header.</a>
+*/
+
+#include <boost/preprocessor/identity.hpp>
+
+//! Essentially macro expands the parameter X twice.
+#define BOOST_PP_EXPAND(X) X
+#endif

include/boost/preprocessor/tuple/elem.hpp

@@ -17,7 +17,7 @@
 <a href="../../../../boost/preprocessor/tuple/elem.hpp">Click here to see the header.</a>
 */
 
-#include <boost/preprocessor/identity.hpp>
+#include <boost/preprocessor/expand.hpp>
 
 //! Expands to the I:th element of an N-tuple.
 /*!
@@ -49,7 +49,7 @@ See also BOOST_PP_LIMIT_TUPLE.
 // this workaround invokes undefined behavior, but it works as desired.
 #  define BOOST_PP_TUPLE_ELEM_DELAY(N,I,T) BOOST_PP_TUPLE##N##_ELEM##I##T
 #else
-#  define BOOST_PP_TUPLE_ELEM_DELAY(N,I,T) BOOST_PP_IDENTITY(BOOST_PP_TUPLE##N##_ELEM##I T)()
+#  define BOOST_PP_TUPLE_ELEM_DELAY(N,I,T) BOOST_PP_EXPAND(BOOST_PP_TUPLE##N##_ELEM##I T)
 #endif
 
 // NOTE: TUPLE_ELEM can be implemented in O(N*N) space and O(N) time instead