public override void ExitRule(IParseTreeListener listener)
        {
            IEvaluatorListener typedListener = listener as IEvaluatorListener;

            if (typedListener != null)
            {
                typedListener.ExitFactor(this);
            }
        }
        public override void ExitRule(IParseTreeListener listener)
        {
            IEvaluatorListener typedListener = listener as IEvaluatorListener;

            if (typedListener != null)
            {
                typedListener.ExitAssignmentCommand(this);
            }
        }
        public override void EnterRule(IParseTreeListener listener)
        {
            IEvaluatorListener typedListener = listener as IEvaluatorListener;

            if (typedListener != null)
            {
                typedListener.EnterVariableFactor(this);
            }
        }
        public override void EnterRule(IParseTreeListener listener)
        {
            IEvaluatorListener typedListener = listener as IEvaluatorListener;

            if (typedListener != null)
            {
                typedListener.EnterExpressionCommand(this);
            }
        }