[rules-dev] feature request: undo-then
Geoffrey De Smet
ge0ffrey.spam at gmail.com
Wed Feb 18 14:57:22 EST 2009
How hard would it be to allow something like this in the DRL?
rule "myRule"
when
t: Total()
... // a bunch of complicated fact constraints
then
t.increment();
undo-then
t.decrement();
end
The current workarounds don't are clunky:
- Writing an negative (opposite) rule isn't efficient: it means
declaring the rule twice effectively. Also the negative rule is usually
using lots of or's and not's which isn't fast.
- Using logical inserts is a more heavy weight (= slower).
Here's another description of this feature request from the user mailing
list:
> Ah, well that's my point of ignorance, then. I was thinking in stateless mode. :) And to do what I suggest in a stateful manner would require a "modifyLogical" type functionality in place of the insertLogical. i.e.
>
> modifyLogical (object) {
> //do this when the condition obtains
> } else {
> //do this when the condition no longer obtains
> }
>
> Could be an interesting functionality to have, though.
--
With kind regards,
Geoffrey De Smet
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