code: public void toRSL(StringBuffer buf, boolean explicitConcat) {
  	buf.append("( ");
  	buf.append( getAttribute() );
  	buf.append(" ");
  	buf.append(getOperatorAsString(operator));
  	buf.append(" ");
  	toRSLSub(getValues(), buf, explicitConcat);
  	buf.append(" )");
      }
docs: Produces a RSL representation of this relation.
  
  @param buf buffer to add the RSL representation to.
  @param explicitConcat if true explicit concatination will
  be used in RSL strings.