// This cd should be modified not to use syntax between optional part.
// The problem in such a case is, which edge do you assign the syntax to?
// If you want syntax there, introduce an extra class.
import edu.neu.ccs.demeter.dj.*;
import java.util.*;

Example = Tree.
Tree ="(" <l> Label
  [<left> Tree] "."
  [<right> Tree] ")".
Label = <v> int.

SummingVisitorDJ = <total> int extends Visitor.
DisplayVisitorDJ = <total> int extends Visitor.
Main = .