Technology, Books and Other Neat Stuff

Here's the first chunk of some work I've been doing for The Register, looking at rules engines and declarative programming.

Businesses run on rules. They define business processes, and describe just what happens if something goes right - or if it goes wrong. Do all the gold-rated customers get a 10% discount, and what happens if one calls customer support? Business rules are part of the decision support systems that underpin every business process.

You can write the rules into your application business logic, but they quickly become spaghetti code, as you try to wrap each and every rule into a self-referential chain of "if then else", "case endcase" and "do while" statements (depending on your language of choice). Business rules change more often than the applications behind them. Debugging every case can add days and complexity to application tests, and meanwhile the business process owner is waiting for you to make the last set of rule changes...

Read more here.