I’m actually interested in any form of backward chaining implemented against one of the Microsoft engines: pseudo-backchaining via forward chaining, more traditional backchaining directly against the rule OM, etc.

The question does occasionally come up from customers who are doing checklist comparisons against other products.

I got tired of hearing about “friends” who had done it, but the example code never arrives. If I had a quarter for every claim to have done it – I’d have…well…a few dollars. (And Charles isn’t one of the guilty parties here.)

I think Charles nails it when he says that the answer is effectively that people aren’t doing it.

I haven’t had a chance to really dig into what Charles has posted yet, so I can’t answer authoritatively about what he built.

And here I have to ask: backward chaining like what?

It turns out that even in that world, there are as many different aspects to backward chaining as there are to forward chaining (you know, those pesky dynamic prios or not, conflict resolution choice, etc questions). The product I worked on before co-creating Blaze Advisor was a very powerful backward chainer, and, boy did we have discussions around the features…

I would love to get a better understanding for the type of backward chaining support you are asking about.
I am quite pleased to see that there seems to be a little bit of interest resurfacing on these technologies.

Thx

The problem I have with Microsoft asking how many of their customers actually do this for real is that we can safely give the answer. Broadly, none. No one does it because no one knows you can do it, understands how to do it or sees any reason why you would want to do it BRE is powerful (with some holes), but lacks the mature tooling and guidance to attract serious attention from most BizTalk developers. The only thing people like me can do is to point out the missed opportunity and pass on the knowledge…which I shall do.

I’m fishing for data regarding the multiple other instances I have heard about. Sure, it’s technically possible. But how many people have actually tried it? And of those people, how many did so for more than just an intellectual exercise?

I do want to do a bit more research on this before I blog. In particular, I’m intrigued by the prospect of implementing what others have called ‘full opportunistic backward chaining’. I am fairly confident this can be done, but I need to look a bit deeper at the idea of automating the instrumentation of rule sets before they are translated to Rete and executed. It would take some non-trivial coding.

Another interesting bit of trivia. Turns out that you can quite easily implement ‘continuous query’ on top of BRE as well. Again, no in-built or explicit support (except, in a sense, the ‘halt’ and ‘execute’ engine methods), but it isn’t hard to do.