/**
* Returns the form stack head element. If the stack is empty,
* the method returns NULL.
*
* @internal
* @static
* @return Opf_Form
*/
public static function topOfStack()
{
if (self::$_stack === null) {
self::$_stack = new SplStack();
}
if (self::$_stack->count() == 0) {
return null;
}
return self::$_stack->top();
}
