if_new - dæmon predicate invoked when instance frame is created
SlotName:
if_new predicate
The if_new dæmon is invoked when a new instance frameis created. When isa is used to create a frame, each of the slots in the inheritance hieararchy is searched for an if_new dæmon. Every if_new dæmon encountered is executed.
Note: the order of execution is top-down. That is, the if_new dæmons highest in the inheritance hierarchy are executed first.
Some of the slots in the patient examples have if_new dæmons.