From sunriseat28@yahoo.com Mon Jan 29 20:23:09 2001
Received: from web1404.mail.yahoo.com (web1404.mail.yahoo.com [128.11.23.168])
	by swi.psy.uva.nl (8.11.2/8.11.2) with SMTP id f0TJN8Z00238
	for <prolog@swi.psy.uva.nl>; Mon, 29 Jan 2001 20:23:08 +0100 (MET)
Received: (qmail 12595 invoked by uid 60001); 29 Jan 2001 19:23:06 -0000
Message-ID: <20010129192306.12594.qmail@web1404.mail.yahoo.com>
Received: from [158.223.52.77] by web1404.mail.yahoo.com; Mon, 29 Jan 2001 11:23:06 PST
Date: Mon, 29 Jan 2001 11:23:06 -0800 (PST)
From: David Yang <sunriseat28@yahoo.com>
To: prolog@swi.psy.uva.nl
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Subject: [SWIPL] The use of 'spy' in SWI-Prolog

Hi,

I have prolems in tracing predicates in SWI-Prolog. I
spy on one predicate but all other predicates get
spied on too. Here is an example:

father(X, Y):- parent(X, Y), male(X).
parent(a,b).
male(a).

?-spy(father).

?- father(a,b).
(1) call: father(a, b)?
(2) call: parent(a,b)?
(2) exit: parent(a,b)?
(2) call: male(a)?
(2) exit: male(a)?
(1) exit: father(a,b)?

yes

But I didn't want to trace 'parent' and 'male'!!! I
can't remove the spy on these two predicates even by:
?- nospy(parent), nospy(male).

Can anybody please help with me on how to spy only
some specific predicates but not all the predicates in
a program?

Thanks!







__________________________________________________
Do You Yahoo!?
Yahoo! Auctions - Buy the things you want at great prices. 
http://auctions.yahoo.com/

