Hi Edson
Thanks for your reply. I guess we’ll try
and code in a work around for now. It would be great to have this feature
though! :-)
I’ve created a feature request in Jira. http://jira.jboss..com/jira/browse/JBRULES-1199
Regards,
_____________________________________________________
Arsalan Zaidi / Capgemini
-
Technical Architect
Mobile Phone: +91 – 9892 8970 03 / www.capgemini.com
Together: the
Collaborative Business Experience
_____________________________________________________
From:
rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org]
On Behalf Of Edson Tirelli
Sent: 14 September 2007 18:42
To:
Subject: Re: [rules-users] How to
use not operator in drool.
Arsalan,
Unfortunately Drools does not have a field constraint
negation operator, mostly because when writing rules, it was not needed, since
you can always negate the constraint itself.
Although, I understand a agree with your use case. My
suggestion is for you to open a JIRA feature request and we will include that
as soon as possible in the product.
Although, meanwhile, the only workaround I can see for your
case is to translate the expression you are using directly into a java or mvel
expression and write it inside an in-line eval.
[]s
Edson
2007/9/14, Arsalan S. Zaidi <arsalan.zaidi@capgemini.com>:
Hi
I'll try to explain the situation that Gaurav finds himself
in. We're working on this problem together and so far, we haven't been able to
crack it.
We're using drools to handle the business rules for an
application. The rules however, are not provided to us in a .drl file, rather,
we get an XLS sheet from the analysts with rules in a different grammar.
We're using ANTLR to read and parse these rules to generate
the drools rules programmatically. However, we're running into problems with
NOT.
The input rules (in the non-drools business language) have a
NOT operator which works like '!' in Java. It flips the Boolean around, so to
speak. So:
NOT((some sub expression which evaluates to TRUE)) == FALSE
MVEL doesn't seem to support this. So how do we simulate it?
If it were only being used with NOT IN, we could manage, but
its use is completely arbitrary. Changes to the input rules or to the input
rules grammar have been (ha ha) ruled out.
Any help would be appreciated.
Regards,
_____________________________________________________
Arsalan Zaidi / Capgemini
-
Technical Architect
Mobile Phone: +91 – 9892 8970 03 / www.capgemini.com
Together: the Collaborative
Business Experience
_____________________________________________________
From: rules-users-bounces@lists.jboss.org
[mailto:rules-users-bounces@lists.jboss.org]
On Behalf Of Anstis, Michael (M.)
Sent: 13 September 2007 13:31
To:
Subject: RE:
[rules-users] How to use not operator in drool.
What dialect do your rules use?
You could also simplify the logic using DeMorgans
Theorem (which might be troublesome to accomplish programmatically)
I don't know whether your example is flawed as the brackets
don't match, but assuming you mean something like this:-
(NOT (G13.1 IN
("1","2","3") OR (G250.8 = Y)))
You can re-write this as
(G13.1NOT IN
("1","2","3") AND G250.8 != Y)
With kind regards,
Mike