Application of rule engines

H.S. Thomas asks...
I couldn't find an appropriate forum to ask this so I'll ask it here.
Why aren't Expert Systems and Rules-Based Engines in common use? They seemed such a good idea 10 years ago and still do. What kinds of systems are they suited for ? You could post your answer in a different thread.
regards

Actually, they are being used, and their use is growing. Nobody uses the term "expert systems" anymore because it's tainted from the "great failure" of A.I. in the late 80's/early 90's; everybody says "rule-based systems." But really, rule-based systems are everywhere. Some of them are very simple, like filtering "rules" in email clients; others are more complex, like business rules engines in enterprise applications. Virtually every application server on the market comes with a rule engine of some kind, and some that don't are planning to include them in upcoming releases. If you're interested in learning about the kinds of applications to which rule engines are being put today... read my book!

like business rules engines in enterprise applications

Actually, I'd asked a question in this forum about Generative Techniques vs Parsers with regard to business rules. I am afraid it went unanswered. Do you favour one over the other and why ?
Or does this work over two levels - generative first to one level which is then parsed to another level.
As an example, take SQL.
You can define business rules which are used to generate the SQL and the SQL parser translates it to another lower level language.
Thank you for answering so promptly.
regards
[ August 29, 2003: Message edited by: HS Thomas ]