This piece of script allows you to make complex set modifier and formula definitions inside of a simple, easily readable and maintainable INLINE or Excel table. You will be able to define filter sets in such a simple way, that each data owner from the business can maintain the definitions (and doesn't need to hold QV-certificate in Design/Developmen) because there won't be a need to know the set modifier syntax. Even set operations (+, -, *, / ) can be defined very easily in a simplified syntax.
Giving you an example: Your formula to calculate the current previous-year's versus this month's sales as a percentage would be