public function add(MergeRuleInterface $rule, $name = null)
	{
	    if (!empty($name)) {
	    	$this->_items[$name] = $rule;
	    } else {
	    	$this->_items[] = $rule;
	    }

	    return $this;
	}
public function add(MergeRuleInterface $rule, $name = null)
	{
	    if (!empty($name)) {
	    	$this->_items[$name] = $rule;
	    } else {
	    	$this->_items[] = $rule;
	    }

	    return $this;
	}
public function add ( MergeRuleInterface $ rule , $ name = null ) { if ( ! empty ( $ name ) ) { $ this -> _items [ $ name ] = $ rule ; } else { $ this -> _items [ ] = $ rule ; } return $ this ; }
add a rule

@param xml\MergeRuleInterface $rule
@param string $name
add a rule