Rules based policy engine

Ryan Meador ryan.d.meador at
Sat Jul 19 23:00:46 CEST 2008

Steven Kurylo <sk at ...> writes:

> > The problem with this is that one needs to think like a programmer to
> > describe your "ideal phone" as a set of rules like these. Not only does
> > one have to think analytically and dissect their concept into orthogonal,
> > machine-checkable rules, but from your examples it's also clear that for
> > such a wide range of possibilities a whole *language* with *expressions*
> > (at least boolean) is necessary.
> I see it as something like sieve.  Its a pretty full language for
> writing rules.  I, as a programmer, I do almost anything I want.  For
> the non-programmers there are various GUIs which allow you to do all
> the simple tasks with a couple clicks.  In fact filter email is fairly
> similar: if these three things are true, do X.  Then I have a stack of
> rules and it goes through them one at time until one is true.
> xpath might work.  There are a few options, though I would try to stay
> away from writing our own if it can be helps.  A plan old python class
> might be enough with function for each possible condition.

I think what we're looking for here is Prolog (or something very similar).  I'd be very interested in contributing to
(and using!) a rule-based system such as this.  In addition to providing an
inference-based rules engine written in first order predicate logic, it has the
unique ability of adding rules with side effects (basically executing native
code) when certain things happen... I think it would work nicely (it basically
is for this purpose).  I already had plans to create a rule-based system for the
moko myself (an adaptation of a prolog-like inference system that I already have
under construction).  Due to the memory and processing constraints on the moko
and the desire to reuse code whenever possible (which I agree with
wholeheartedly), I think going with Prolog is probably a better choice than
trying to finish my hacked-together and unproven inference engine.

Now if only my Freerunner would arrive... dunno why it's been delayed by a week
before shipping.

Ryan Meador

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