@Override
	public Object evaluate(ArrayList<Context1> pila_basura) throws Exception {
		try{
		StringBuilder output = new StringBuilder();

		for (Evaluator e : lista) {
			if (e != null) {
				if (e instanceof ReturnEvaluator) {
					return e.evaluate(pila);
				}
				Object ob;
				ob = e.evaluate(pila);
				if (ob != null) {
					if (ob instanceof Double)
						output.append(((Double) ob).toString());
					else
						output.append(ob.toString());
				}

				if (e instanceof WhileEvaluator) {
					if (((WhileEvaluator) e).getBandera())
						return ob;
				}
				if (e instanceof IfEvaluator) {
					if (((IfEvaluator) e).getBandera())
						return ob;
				}
			}
		}
		return output.toString();
		}finally{
			//pila.remove(pila.size() - 1);
		}
	}