Try this:
(deftemplate Person
(slot Name (type STRING))
(multislot Ancestors)
)
(assert
(Person (Name "a")
(Ancestors (assert (Person (Name "b")))
(assert (Person (Name "c")))
)
)
)
(defrule removePersonReferences
(remove-person ?name)
?person <- (Person (Name ?name))
?decendent <- (Person (Ancestors $?pre ?person $?post))
=>
(modify
?decendent (Ancestors (create$ ?pre ?post))
)
)
(defrule removePerson
?trigger <- (remove-person ?name)
?person <- (Person (Name ?name))
(not (Person (Ancestors $?pre ?person $?post)))
=>
(retract ?person)
(retract ?trigger)
)
Output from run:
Jess> (watch all)
TRUE
Jess> (batch "..\\test2.jess")
==> f-0 (MAIN::Person (Name "b") (Ancestors ))
==> f-1 (MAIN::Person (Name "c") (Ancestors ))
==> f-2 (MAIN::Person (Name "a") (Ancestors <Fact-0> <Fact-1>))
MAIN::removePersonReferences: +1+1+1+1+2+1+2+t
MAIN::removePerson: =1=1=1=1=2=1+2+t
TRUE
Jess> (assert (remove-person "c"))
==> f-3 (MAIN::remove-person "c")
==> Activation: MAIN::removePersonReferences : f-3, f-1, f-2
<Fact-3>
Jess> (run)
FIRE 1 MAIN::removePersonReferences f-3, f-1, f-2
==> Activation: MAIN::removePerson : f-3, f-1,
<=> f-2 (MAIN::Person (Name "a") (Ancestors <Fact-0>))
FIRE 2 MAIN::removePerson f-3, f-1,
<== f-1 (MAIN::Person (Name "c") (Ancestors ))
<== f-3 (MAIN::remove-person "c")
2
Jess> (facts)
f-0 (MAIN::Person (Name "b") (Ancestors ))
f-2 (MAIN::Person (Name "a") (Ancestors <Fact-0>))
For a total of 2 facts.
Jess>
You will have to arrange to have one of your rules assert the
(remove-person) fact.
Also, you could use a defquery to find all related (Person) facts that
reference to-be-removed person fact and then modify each of the returned
facts and their Ancestor multifields.
Good luck!
alan
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of portalguy
> Sent: Wednesday, June 29, 2005 10:01 AM
> To: jess-users@sandia.gov
> Subject: JESS: Remove all references pointing to the
> retracted fact from the slots
>
>
> Hi,
> I'm trying to find the quickest way to setting references in
> slots to a retracted fact to nil or remove them if in a
> multislot. For instance if I have the following template:
>
> (deftemplate Person
> (slot Name (type STRING))
> (multislot Ancestors)
> )
>
> and the following facts:
>
> (assert
> (Person (Name "a")
> (Ancestors (assert (Person (Name "b")))
> (assert (Person (Name "c")))
> )
> )
> )
>
> f-0 (MAIN::initial-fact)
> f-1 (MAIN::Person (Name "b") (Ancestors ))
> f-2 (MAIN::Person (Name "c") (Ancestors ))
> f-3 (MAIN::Person (Name "a") (Ancestors <Fact-1> <Fact-2>))
> For a total of 4 facts in module MAIN.
>
> Now if I remove say fact 1 I need to remove it from ancestors
> in fact 3 but if I only do (retract 1) I end up with the
> following and as you can see fact 3 still hold reference to
> none existing fact 1:
> f-0 (MAIN::initial-fact)
> f-2 (MAIN::Person (Name "c") (Ancestors ))
> f-3 (MAIN::Person (Name "a") (Ancestors <Fact-1> <Fact-2>))
> For a total of 3 facts in module MAIN.
>
> The question is what is the quickest way to clean up the
> reference issue, other than going through every slot and
> verifying that it is not pointing to a none existing fact.
>
> Thanks
>
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