I think Steffen Luypaert wrote: [Charset iso-8859-1 unsupported, filtering to ASCII...]
> Now, the problem isn't to get the correct sum. In a former version of > my application I calculated it by getting all accounts with a defquery > and then using the returned Iterator object to get the desired sum. My > problem is to make the sum fact logically dependent of all account > facts used to compute it. If an old account fact is modified or > retracted, or a new one is asserted, I want the sum fact to be > retracted automatically. The easiest way to do this would be with an event handler. Just watch for any FACT events, and if the Fact object is an "account" fact, then retract the sum fact. A lot simpler than what you showed here. --------------------------------------------------------- Ernest Friedman-Hill Science and Engineering PSEs Phone: (925) 294-2154 Sandia National Labs FAX: (925) 294-2234 PO Box 969, MS 9012 [EMAIL PROTECTED] Livermore, CA 94550 http://herzberg.ca.sandia.gov -------------------------------------------------------------------- To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED] --------------------------------------------------------------------