diff --git a/include/boost/preprocessor/expr_if.hpp b/include/boost/preprocessor/expr_if.hpp
index be893a0..4bf77cb 100644
--- a/include/boost/preprocessor/expr_if.hpp
+++ b/include/boost/preprocessor/expr_if.hpp
@@ -13,9 +13,6 @@
  * See http://www.boost.org for most recent version.
  */
 
-// pm:  not necessary if using manual delay
-// #include <boost/preprocessor/detail/cat.hpp>
-
 #include <boost/preprocessor/logical/bool.hpp>
 
 /** <p>Expands to <code>EXPR</code> if <code>COND != 0</code> and to nothing if <code>COND == 0</code>.</p>
diff --git a/include/boost/preprocessor/if.hpp b/include/boost/preprocessor/if.hpp
index 6f90104..0ade099 100644
--- a/include/boost/preprocessor/if.hpp
+++ b/include/boost/preprocessor/if.hpp
@@ -13,9 +13,6 @@
  * See http://www.boost.org for most recent version.
  */
 
-// pm:  not necessary if using manual delay
-// #include <boost/preprocessor/detail/cat.hpp>
-
 #include <boost/preprocessor/logical/bool.hpp>
 
 /** <p>Expands to <code>THEN</code> if <code>COND != 0</code> and <code>ELSE</code> if
@@ -35,11 +32,11 @@
   <li><a href="../../test/preprocessor_test.cpp">preprocessor_test.cpp</a></li>
 </ul>
 */
-#define BOOST_PP_IF(COND,THEN,ELSE) BOOST_PP_IF_BOOL(BOOST_PP_BOOL(COND),THEN,ELSE) /* original:  BOOST_PP_DETAIL_CAT2(BOOST_PP_IF,BOOST_PP_BOOL(COND))(ELSE,THEN) */
+#define BOOST_PP_IF(COND,THEN,ELSE) BOOST_PP_IF_BOOL(BOOST_PP_BOOL(COND),ELSE,THEN)
 
-#define BOOST_PP_IF_BOOL(COND,THEN,ELSE) BOOST_PP_IF_BOOL_DELAY(COND,THEN,ELSE)
-#define BOOST_PP_IF_BOOL_DELAY(COND,THEN,ELSE) BOOST_PP_IF##COND(THEN,ELSE)
+#define BOOST_PP_IF_BOOL(C,E,T) BOOST_PP_IF_BOOL_DELAY(C,E,T)
+#define BOOST_PP_IF_BOOL_DELAY(C,E,T) BOOST_PP_IF##C(E,T)
 
-#define BOOST_PP_IF0(T,E) E // BOOST_PP_IF0(E,T) E
-#define BOOST_PP_IF1(T,E) T // BOOST_PP_IF1(E,T) T
+#define BOOST_PP_IF0(E,T) E
+#define BOOST_PP_IF1(E,T) T
 #endif