The following works perfectly in Jess 6.0a5:
(deftemplate user (slot name))
(deftemplate user-location (slot user) (slot location))
(bind ?john (assert (user (name john))))
(assert (user-location (user ?john) (location A)))
(defrule print-name-of-user-at-location
(user-location (location A) (user ?u))
=>
(printout t (fact-slot-value ?u name) crlf))
(run)
It prints "john." If you get a different result, remember that Jess 6
is experimental software; upgrade to the latest version and try
again.
I think Jerome BERNARD wrote:
> I am using Jess 6.
>
> I tried to do the following which works:
> (bind ?john (assert (user (name john))))
>
> and then do that which doesn't work:
> (assert (user-location (user ?john) (location A)))
>
> So based on what you said, i can't figure what's wrong in what i did.
>
>
> -----Message d'origine-----
> De : friedman_hill ernest j [mailto:[EMAIL PROTECTED]]
> Envoye : mardi 13 mars 2001 17:22
> A : =?iso-8859-1?Q?J=E9r=F4me_BERNARD?=
> Cc : [EMAIL PROTECTED]
> Objet : Re: JESS: How to have a slot value being a reference to another
> object?
>
>
> In previous versions of Jess, you'd have to use a slot in "user" as a
> sort of identifier; i.e., user-location's user slot could contain the
> name of a user. You can't use a numeric fact-id, because those change
> when the fact is modified. Then when you write a rule, you have to
> match on that slot
>
> (defrule move-user-to-location-A
> (user (name ?name))
> =>
> (assert (user-location (user ?name) (location A))))
>
> (defrule process-user-at-location-A
> (user-location (user ?name) (location A))
> ?u <- (user (name ?name))
> =>
> (do-something-to ?u))
>
> In Jess 6.x, bound fact ids like ?u are actually references to Fact
> objects, not just numbers (although they can be easily, and sometimes
> transparently, converted to numbers.) So in Jess 6, you can do
>
> (defrule move-user-to-location-A
> ?u <- (user)
> =>
> (assert (user-location (user ?u) (location A))))
>
> (defrule process-user-at-location-A
> ?u <- (user)
> (user-location (user ?u) (location A))
> =>
> (do-something-to ?u))
>
>
> I think =?iso-8859-1?Q?J=E9r=F4me_BERNARD?= wrote:
> [Charset iso-8859-1 unsupported, filtering to ASCII...]
> > Hi all!
> >
> > I have defined 3 objects such as those ones.
> > (deftemplate user (slot name) )
> > (deftemplate product (slot productID) (slot location) )
> > (deftemplate user-location (slot user) (slot location) )
> >
> > And have asserted the following facts:
> > (assert(product (productID 1) (location A)))
> > (assert(product (productID 2) (location B)))
> > (assert(product (productID 3) (location C)))
> > (assert(user (name john)))
> > (assert(user (name foo)))
> > (assert(user (name bar)))
> >
> >
> > Now what I want to do is to assert a user-location fact such as the user
> > slot would be the refence to one of the asserted users and the location
> > would be a simple string.
> > I tried to bind the fact id to a variable, but then since I have a fact id
> > and not a reference, I don't know what to do with it.
> >
> > I am probably going into the wrong way, but i can't figure out how to
> solve
> > that...
> >
> > Can someone help me?
> >
> >
> > Thank you in advance.
> >
> > Regards,
> > J_r_me BERNARD.
> >
> >
> > ---------------------------------------------------------------------
> > 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]
> > ---------------------------------------------------------------------
> >
>
>
>
> ---------------------------------------------------------
> Ernest Friedman-Hill
> Distributed Systems Research Phone: (925) 294-2154
> Sandia National Labs FAX: (925) 294-2234
> Org. 8920, MS 9012 [EMAIL PROTECTED]
> PO Box 969 http://herzberg.ca.sandia.gov
> Livermore, CA 94550
>
---------------------------------------------------------
Ernest Friedman-Hill
Distributed Systems Research Phone: (925) 294-2154
Sandia National Labs FAX: (925) 294-2234
Org. 8920, MS 9012 [EMAIL PROTECTED]
PO Box 969 http://herzberg.ca.sandia.gov
Livermore, CA 94550
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