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

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

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