Docs updated

[SVN r13170]

include/boost/preprocessor/tuple.hpp

@@ -13,9 +13,27 @@
  * See http://www.boost.org for most recent version.
  */
 
-/** <p>Includes all tuple headers.</p> */
+/** <p>Includes all tuple headers.</p>
+
+<p>A tuple is a fixed size collection of elements.</p>
+
+<p>In the preprocessor library, tuples are represented like macro parameter
+lists. Thus an element of a tuple can be any sequence of tokens that
+constitutes a single macro parameter.</p>
+
+<p>Examples of tuples:</p>
+
+<pre>
+  (const, volatile)    // 2-tuple
+  (*, /, %)            // 3-tuple
+  (1, "2", '3', (4,5)) // 4-tuple
+</pre>
+
+<p>Tuples can be used for representing structured data.</p>
+*/
 
 #include <boost/preprocessor/tuple/eat.hpp>
 #include <boost/preprocessor/tuple/elem.hpp>
+#include <boost/preprocessor/tuple/reverse.hpp>
 #include <boost/preprocessor/tuple/to_list.hpp>
 #endif