Why wouldn't a simple (defrule r (k (when ?w)) => (schedule-timer-alert (+ ?w 3000)) )
be sufficient? -W On 21 July 2010 16:00, Ernest Friedman-Hill <ejfr...@sandia.gov> wrote: > This is quite clever, but as you found, this won't work due to limitations > in the implementation. But you could skip backward chaining altogether and > just do something like > > (defrule r > (k (when ?w&:(progn (schedule-time-alert (+ ?w 3000)) TRUE))) > (time (when =(+ ?w 3000))) ; a time fact 3 seconds after k is expected > => > (printout t "3 seconds after k!" crlf) ) > > You would not need the progn/TRUE if schedule-time-alert returned a true > value. > > > On Jul 21, 2010, at 5:59 AM, Henrique Lopes Cardoso wrote: > >> Hi, >> >> I was trying to make a rule that fires a few seconds after a fact is >> asserted. Here is my experiment: >> >> (deftemplate time (slot when)) >> (do-backward-chaining time) >> >> (defrule do-time >> (need-time (when ?w)) >> => >> (schedule-time-alert ?w) ) >> >> (deftemplate k >> (slot when (default-dynamic (call System currentTimeMillis))) ) >> >> (defrule r >> (k (when ?w)) >> (time (when =(+ ?w 3000))) ; a time fact 3 seconds after k is expected >> => >> (printout t "3 seconds after k!" crlf) ) >> >> Function schedule-time-alert is implemented in Java and is supposed to >> add a fact at the indicated time. >> While this approach looks pretty clean to me, it does not even compile. >> I am getting a "Can't use funcalls in backchained patterns when", in >> rule r. This does not seem to be documented (at least I did not find it). >> >> There is a work arround described in >> http://www.jessrules.com/jess/FAQ.shtml#Q9 >> That approach has been suggested in previous e-mail threads, I have >> noticed. >> But while it seems to work, it is also much more CPU-intensive, as a >> number of time events (idle facts in faq Q9) would be added for no reason. >> >> Any thoughts? >> >> Thanks. >> >> Henrique >> >> >> >> -------------------------------------------------------------------- >> To unsubscribe, send the words 'unsubscribe jess-users y...@address.com' >> in the BODY of a message to majord...@sandia.gov, NOT to the list >> (use your own address!) List problems? Notify owner-jess-us...@sandia.gov. >> -------------------------------------------------------------------- > > --------------------------------------------------------- > Ernest Friedman-Hill > Informatics & Decision Sciences Phone: (925) 294-2154 > Sandia National Labs > PO Box 969, MS 9012 ejfr...@sandia.gov > Livermore, CA 94550 http://www.jessrules.com > > > > > > -------------------------------------------------------------------- > To unsubscribe, send the words 'unsubscribe jess-users y...@address.com' > in the BODY of a message to majord...@sandia.gov, NOT to the list > (use your own address!) List problems? Notify owner-jess-us...@sandia.gov. > -------------------------------------------------------------------- > > -------------------------------------------------------------------- To unsubscribe, send the words 'unsubscribe jess-users y...@address.com' in the BODY of a message to majord...@sandia.gov, NOT to the list (use your own address!) List problems? Notify owner-jess-us...@sandia.gov. --------------------------------------------------------------------
