Thanks for the quick reply.

Your solution is perfect. I had seen in the doc that you could use "return" to prevent the adviced function to be called but I didn't think of it as a solution to my problem... That works great, though I was kind of expecting an infinite loop but it seems smart enough not to call the advice again.

Thanks for the help.
BTW, I'm working on a binding Jess<->OWL that would rely on Jena if people are interested... I know there exists a bridge for OWL/SWRL in Protege but I was not very happy with it and also Jena is much lighter than Protege.



Le 07/10/2010 17:03, Ernest Friedman-Hill a écrit :
Yes, a function can have only one advice. This wasn't originally the case, but experience showed that allowing multiple advice per function caused problems -- it was too easy to create infinite loops, for example.

You can solve your problem with a before-advice which unbinds the variables, calls bsave explicitly, rebinds the variables, and then returns. If you check the documentation, it explains that explicitly returning from a before-advice will result in the adviced function not being called automatically.


On Oct 7, 2010, at 8:44 AM, Gaëtan Pruvost wrote:

Hi everybody,

I have a problem with defadvice's behavior. It looks like you can't add both a "before" and an "after" advice to the same function.
Here is an example that demonstrates it

(deffunction f ()
    (printout t "during f" crlf))

(defadvice before f (printout t "before f" crlf))
(defadvice after f (printout t "after f" crlf))

(f)


It prints:
Jess> (batch "test.clp")
during f
after f
Jess>

Looks like the after overwrote the before one and there is no way to define both at the same time... I'm new to Jess so I hope this question is not stupid but i looked in documentation and in the old mailling-list messages and found no explaination for it. Is it the intended behaviour (in which case it would be good to precise it in the doc) or a bug? I'm using the last Jess71p2.

I needed this to unbind global variables before a bsave and rebind after the bsave (this variable refers to a java Logger which is not serializable). I've found another solution wihtout using defadvice but I find the defadvice more elegant.


Best regards
--
***********************************
Gaëtan PRUVOST

LIMSI-CNRS BP 133
91403 Orsay Cedex France
Tel:+33 1 69858110

http://www.limsi.fr/Individu/pruvost/
***********************************
<gaetan_pruvost.vcf>

---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences, Sandia National Laboratories
PO Box 969, MS 9012, Livermore, CA 94550
http://www.jessrules.com








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