Re: JESS: Defrule bind get-member crashes: Bad slot value at token '('.

Hi Jevon,

Read number 17 in our FAQ: http://www.jessrules.com/jess/FAQ.shtml#Q17

The right way to write your final rule might be something like this,  
depending on what kind of facts these are:

(defrule debug-four
	(BooleanPropertyImpl (OBJECT ?property))
	(PageImpl (OBJECT ?container))
	(test (progn
		(bind ?children (get-member ?container children)))
		(member$ ?property ?children)))
	=>
	((System.out) println "...")
)


On Mar 4, 2011, at 2:18 AM, Jevon Wright wrote:

> Hi all,
>
> I am trying to write a Jess rule program to perform inference on an
> EMF-based model instance. I can successfully load all of the model
> elements into Jess, and check that these facts all exist:
>
> (defrule debug-one
> 	?property <- (BooleanPropertyImpl)
> 	=>
> 	((System.out) println "Found property:")
> 	((System.out) println ?property)
> )
>
> This rule works fine, and all of the BooleanPropertyImpl in the model
> are found successfully. But I am having trouble with accessing members
> of the elements, using either get-member, or call, or bind.
>
> (defrule debug-three
> 	?container <- (BooleanPropertyImpl)
> 	(bind ?name (get-member ?container name))
> 	=>
> 	((System.out) println "Found name:")
> 	((System.out) println ?name)
> )
>
> I expect this to bind object.getName() to ?name, but instead the  
> parse fails:
>
> Jess reported an error in routine Jesp.parsePattern.
>  Message: Bad slot value at token '('.
>  Program text: ( defrule debug-three ?container <- (
> BooleanPropertyImpl ) ( bind ?name (  at line 44 in file
> rules/jess-test.clp.
> 	at jess.Jesp.error(Unknown Source)
>
> What does this mean? Is this a syntax error? Is this an error with my
> Java objects? Am I missing a runtime library? Should I be importing
> other packages? I can't think of any other way to approach this
> problem.
>
> The reason I am using get-member is that I was trying to see if an
> elements' List contains another element:
>
> (defrule debug-four
> 	?property <- (BooleanPropertyImpl)
> 	?container <- (PageImpl)
> 	(bind ?children (get-member ?container children)))
> 	(member$ ?property ?children)
> 	=>
> 	((System.out) println "...")
> )
>
> However, this also fails with the exception above. Any ideas or
> suggestions would be most welcome. :)
>
> Thanks
> Jevon
>
>
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Ernest Friedman-Hill
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Sandia National Labs
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