Bike.Interpreter.Interpreter.OpDoubleMinus C# (CSharp) Метод

        public object OpDoubleMinus(object value)
        {
            if (value == null)
                throw ErrorFactory.CreateTypeError( "Invalid operand type: 'null'");
            if (value is BikeNumber)
                return new BikeNumber(((BikeNumber)value).Value - 1);
            throw ErrorFactory.CreateTypeError(string.Format("Invalid operand type: {0}--", value));
        }