Rule

A 'Rule' is a computer instruction that sets up the what a software application will do next.

A rule is very often of the form

"IF this condition is true THEN do this OR ELSE do this"

For example an expert system might have a rule that says: "If person has red spots then she might have measles'.

Or an online shopping cart application might have been programmed to react when a rule is met

"If the customer has hesitated for more than 10 seconds in filling in their order details, then pop up a help screen"

 

2020-10