public class DomainRangeList extends List {
   public DomainRangeList(DomainRange dr, DomainRangeList drl) {
      this.thing = dr;
      this.rest  = drl;
   }

   public DomainRange     getDomainRange() { return (DomainRange)thing;    }
   public DomainRangeList getRest()        { return (DomainRangeList)rest; }
}