static function make( $nt, $la = null ){
		if( isset(self::$uindex[$nt][$la]) ){
			return self::$uindex[$nt][$la];
		}
		return new LRStation( $nt, $la );
	}
static function make( $nt, $la = null ){
		if( isset(self::$uindex[$nt][$la]) ){
			return self::$uindex[$nt][$la];
		}
		return new LRStation( $nt, $la );
	}
static function make ( $ nt , $ la = null ) { if ( isset ( self :: $ uindex [ $ nt ] [ $ la ] ) ) { return self :: $ uindex [ $ nt ] [ $ la ] ; } return new LRStation ( $ nt , $ la ) ; }
Factory method to ensure unique object instances globally
And stored in global index in an accessible way
@param int non-terminal symbol
@param int|string optional lookahead symbol
@return LRStation
Factory method to ensure unique object instances globally And stored in global index in an accessible way