private double Eval(Msg[] input)
        {
            var parser = new MiniInterperter();
            var result = Language.Parse(parser, input).Result;

            return(result);
        }
        private double Eval(MiniInterperter context, string expr)
        {
            double value = Language.Parse(context, expr).Result;

            return(value);
        }
        private double Eval(string expr)
        {
            var parser = new MiniInterperter();

            return(Eval(parser, expr));
        }