- Added information about NULL as the default parameter value

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@257695 c90b9560-bf6c-de11-be94-00142212c4b1

language/oop5/typehinting.xml

@@ -1,11 +1,13 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.5 $ -->
+<!-- $Revision: 1.6 $ -->
  <sect1 xml:id="language.oop5.typehinting" xmlns="http://docbook.org/ns/docbook">
   <title>Type Hinting</title>
   <para>
    PHP 5 introduces Type Hinting. Functions are now able to force parameters
    to be objects (by specifying the name of the class in the function
-   prototype) or arrays (since PHP 5.1).
+   prototype) or arrays (since PHP 5.1). However, if <type>NULL</type> is used
+   as the default parameter value, it will be allowed as an argument for any 
+   later call.
   </para>
   
   <example>
@@ -97,6 +99,24 @@ function MyFunction (MyClass $foo) {
 // Works
 $myclass = new MyClass;
 MyFunction($myclass);
+?>
+]]>
+   </programlisting>
+   <para>
+    Type hinting allowing NULL value:
+   </para>
+    <programlisting role="php">
+<![CDATA[
+<?php
+
+/* Accepting NULL value */
+function test(stdClass $obj = NULL) {
+
+}
+
+test(NULL);
+test(new stdClass);
+
 ?>
 ]]>
    </programlisting>