MartiFowler.com: production rule.
Organize logic through a set of production rules, each having a condition and an action.
The system runs the rules on the data it has through a series of cycles, each cycle identifying the rules whose conditions match, then executes the rules' actions.
A Production Rule System is usually at the heart of an expert system.
StackOverflow: rules engine pros and cons.
SOA architectures may do the same as rules engine.
This stackOverflow page recommends: DSL (domain specific language) Programming, expert system and Rete net, logic programming language Prolog, Decision Learning Tree (ID3 Algorithm).