[rules-users] "Trying to create a restriction for an empty restriction" error

[Edson Tirelli]

    Yuri,

    We support -> for backward compatibility and I confess I haven't seen
this error before. I guess it may be complaining about the variable binding:

      $age : age -> (Math.abs($age - c1.age) < 10),

    Anyway, if you can please open a JIRA for that.
    An yes, we prefer to not use -> anymore, so if you are able to change
this during your upgrade, then it is better to simply use the "eval" keyword
instead of the ->. Example:

   c2:Child( eval(Math.abs(age - c1.age) < 10), ...)

    Note that if that is the only place where you use the "age" field, the
binding is automatically created for you. You don't need to do it explicitly
anymore. If you need the binding for other purposes, you can do a regular
binding:

   c2:Child( $age : age, eval(Math.abs($age - c1.age) < 10), ...)

    Regarding your second questions, the answer is yes. We now support
totally nestable && and || as constraints and restriction connectors. So:

   p2: Person(
            (sex == "M" && p1.sex == "F") || (sex == "F" && p1.sex == "M")
         )

     () are optional and && has higher priority than ||.
     We already updated docs for such things in the manual. I would like to
ask you to read and please provide feedback and even patches for parts of
the text that eventually are not clear:

http://labs.jboss.com/file-access/default/members/drools/freezone/docs/4.0.0.13773GA/html/index.html

    Section 6.5.2.

    []s
    Edson


2007/7/25, Yuri <ydewit at gmail.com>:
>
> I am migrating my 3.0.6 rules into 4.0 but I am getting the following
> error in
> Drools IDE:
>
> "Trying to create a restriction for an empty restriction"
>
> I am basically using an inline-eval (I believe this is the new terminology
> for
> the ->() construct):
>
> Rule
> when
>    c1:Child()
>    c2:Child(
>       age -> (Math.abs(age - c1.age) < 10),
>       ...)
> then
>    ...
> end
>
> If I remove the "age -> ..." line the error goes away.
>
> Along the same lines I am also wondering if there is a better way (aside
> from
> using "->()", which has a lower perf as I understand it) of doing the
> following:
>
> Rule
> when
>    p1: Person()
>    p2: Person(
>          ...,
>          sex -> (
>             (sex == "M" && p1.sex == "F")
>             || (sex == "F" && p1.sex == "M")
>          )
>    )
> then
>    insert(new Couple(p1, p2));
> end
>
> thanks,
>
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>



-- 
  Edson Tirelli
  Software Engineer - JBoss Rules Core Developer
  Office: +55 11 3529-6000
  Mobile: +55 11 9287-5646
  JBoss, a division of Red Hat @ www.jboss.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/rules-users/attachments/20070726/3b145760/attachment.html