function &instance()
 {
     if (class_exists('debug_mock')) {
         $impl =& instantiate_object('debug_mock');
     } else {
         $impl =& instantiate_object('debug');
     }
     return $impl;
 }

	function & instance()
	{
		return instantiate_object('stats_search_phrase');
	}

	function & instance()
	{	
		$obj =&	instantiate_object('access_policy');
		return $obj;
	}

	function &instance()
	{
		$obj =&	instantiate_object('search_fetcher');
		return $obj;
	}

 function & instance($cart_id = null, $handler = null)
 {
   $obj =& instantiate_object('cart', array($cart_id, $handler));
   return $obj;
 }

 function &instance($db_table_name)
 {
     $obj =& instantiate_object($db_table_name . '_db_table', '/core/db_tables/');
     return $obj;
 }

 function &instance()
 {
     $obj =& instantiate_object('request');
     return $obj;
 }

 function &instance()
 {
   return instantiate_object('sys');
 }

	function & instance()
	{
		$obj =&	instantiate_object('full_text_indexer');
		return $obj;
	}

	function &instance($driver = null)
	{
		$obj =&	instantiate_object('tree', array($driver));
		return $obj;
	}

 function & instance($class_name)
 {
   include_class($class_name, '/core/model/search/normalizers/');
   $obj =&	instantiate_object($class_name);
   return $obj;
 }

 function &instance()
 {
     $impl =& instantiate_object('debug_mock');
     return $impl;
 }

 function &instance($class_name)
 {
     include_class($class_name, '/core/model/site_objects/');
     $obj =& instantiate_object($class_name);
     return $obj;
 }