Re: JESS: assertFact() and java.lang.String

STRING and SYMBOL are two different data types; here's one of the many  
forum threads where this has been discussed:

http://www.mail-archive.com/[email protected]/msg07900.html

Calling 'new Value("a")' creates a value of type STRING, while the  
values in your retract-string call are SYMBOLs. Check out the other  
constructors of jess.Value; they are documented extensively.



On Nov 9, 2010, at 12:23 PM, kartik tadanki wrote:

> Hi,
>
> Question How can I use Value object to put in simple strings instead  
> of java.lang.String instances.?
>
> -I wish to be able to assert facts from Java such that the rules in  
> the knowledge base can apply to them.
> -Currently, I use assertString().
> -When I use assertFact() the rules do not apply to the fact as with  
> assertString()
> This is because the slot values are now java.lang.String instances.
>
> How can I avoid building the string for assertString() and use  
> assertFact() such that the rules
> process facts thus asserted?
>
>
> My code:
> =============================================
> // (deftemplate Authorization (slot subject ) (slot predicate) (slot  
> object))
>
> //create fact
> Fact fact = new Fact("Authorization", r);
>
> set values
> Value va = new Value("a");
> fact.setSlotValue("subject", va);
> Value vb = new Value("b");
> fact.setSlotValue("predicate", vb);
> Value vc = new Value("c");
> fact.setSlotValue("object", vc);
>
> //assert the fact
> rete.assertFact(fact);
>
> // this retractString has no effect.
> rete.retractString("(Authorization (subject a) (object c) (predicate  
> b))");
> =============================================
>
>
> Thank you,
> -Kartik Tadanki
>
>

---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences          Phone: (925) 294-2154
Sandia National Labs
PO Box 969, MS 9012                            [email protected]
Livermore, CA 94550                             http://www.jessrules.com





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