001    package lrs.visitor;
002    import logic.*;
003    
004    // Defines an interface for comparable objects.
005    
006    public interface IComparable
007    {
008        public abstract IBoolean compare(IComparable x);
009        
010        // not really necessary, but makes life a little easier.
011        public abstract IBoolean equals(IComparable x);
012        
013    }