if (s1 ==null || s2==null) return false; else return s1.startsWith(s2);
return s1.startsWith(s2);
	private boolean startsWith(VTDNav vn){	    String s1 = argumentList.e.evalString(vn);	    String s2 = argumentList.next.e.evalString(vn);	    if (s1 ==null || s2==null)	        return false;	    else	        return s1.startsWith(s2); 	}