public Object evaluate() throws Exception {
Stack s = popValues(parameterCount);
Collections.reverse(s);
Evaluator eval = Evaluator.getEvaluator(evaluatorClass);
try {
Object o = eval.evaluate(s);
stack.set(stack.pointer, o.toString());
//stack.pointer++;
return o;
} catch (Exception e) {
throw new WrongValuesException(simbol);