This script allows you to create "conditional states". A conditional state is simply a placeholder for other states, depending on the conditions at the time the state is applied.
For example, suppose you have a skill that adds a Weak Poison state to a target if it is not already poisoned, and adds a Strong Poison state if it has Weak Poison inflicted. You can use a formula to determine whether the weak poisonhas been added or not to determine which state should be added.