prev = s;
    public vDescriptor Call() {	StringWriter w = new StringWriter();	PrintWriter p = new PrintWriter(w);	(new Exception()).printStackTrace(p);	LineNumberReader r =	    new LineNumberReader(new StringReader(w.toString()));	String s;	int n = 0;	try {	    while ((s = r.readLine()) != null) {		if (s.indexOf("p_l$") >= 0) {		    n++;		}	    }	} catch (IOException e) {	}	return vInteger.New(n);    }