I've been thinking about something i think might make authoring rules easier. I've found that often in rules only one of the patterns is the reactive trigger pattern, and I use techniques to stop the reactivity of other patterns; such as using watch(!*). However even with !* you'll get reactivity when something is first inserted, just not after modificiation. So I've been thinking about formalising this.
To a certain degree the use of queries already have this, via ?. When ? is used the query is executed when left triggered only, further it is not left open and there is no reactivity. There are plans to allow patterns to also obey ?. Such that if you did ?Person() it would only join when left triggered and there would be no reactivity from Person itself. However I'm not sure this is enough, while I may not want reactivity from inserts and modifies, I may still want retract to be obeyed. Assuming A and B are class definitions and we allowed ? on ground terms. The following would ignore all B insertions until it is left triggered via an A propagation. However no link is maintained, so we do not receive B modifications or retracts either - so the behaviour is exactly like queries. $a : A() ?B($a; ) Do we want a half measure that ignores modifies, but allows retracts? Maybe using a double ?? $a : A() ??B($a; ) Or is the default query behaviour adequate? Or are there some other alternatives people can think of? I've been thinking about the same for rule groups too. If we have "rule groups" maybe only certain facts will trigger evaluations for rules. But again not sure what a syntax would look like. Mark _______________________________________________ rules-dev mailing list rules-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-dev
