package edu.stanford.rt.credential;

/**
 * @author Ninghui Li, Sandra Qiu<br>
 *
    A marker interface. 
    
    A PrincipalExpression can be the following:
    A Principal, a Role, a LinkedRole, or a RoleIntersection.
 */
public interface PrincipalExpression extends java.io.Serializable
{
    public String toString(String indent);
}