diff --git a/language/functions.xml b/language/functions.xml
index f8d374ef15..0228f9a17d 100644
--- a/language/functions.xml
+++ b/language/functions.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.63 $ -->
+<!-- $Revision: 1.64 $ -->
  <chapter id="language.functions">
   <title>Functions</title>
 
@@ -259,6 +259,7 @@ function makecoffee($type = "cappuccino")
     return "Making a cup of $type.\n";
 }
 echo makecoffee();
+echo makecoffee(null);
 echo makecoffee("espresso");
 ?>
 ]]>
@@ -272,6 +273,7 @@ echo makecoffee("espresso");
     <para>
      <screen>
 Making a cup of cappuccino.
+Making a cup of .
 Making a cup of espresso.
      </screen>
     </para>