--- doc/src/sgml/ref/alter_extension.sgml.bak	2011-04-05 01:48:24.013675393 +0100
+++ doc/src/sgml/ref/alter_extension.sgml	2011-04-05 01:55:09.485454466 +0100
@@ -218,6 +218,18 @@
     </varlistentry>
 
     <varlistentry>
+     <term><replaceable class="parameter">left_type</replaceable></term>
+     <term><replaceable class="parameter">right_type</replaceable></term>
+     <listitem>
+      <para>
+       The data types of the operator's left and right operands.
+       If the operator is unary, the missing argument must be replaced
+       by <literal>NONE</>.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry>
      <term><replaceable class="parameter">argname</replaceable></term>
 
      <listitem>