[rules-users] Order of operations

[Edson Tirelli]

   Joe,

   Thanks, I added this information to the ticket too. Mike is already
taking care of the problem.

   In case you want to follow the progress:

http://jira.codehaus.org/browse/MVEL-83

    []s
    Edson

2008/4/9 Joe White <Joe.White at recondotech.com>:

>  Another bug that  I just came across while working on getting my parens
> to work involved not handling scoped numbers properly. Similar to the
> previous one, but different in that it ends the expression evaluation
> prematurely. See the drl and result below:
>
>
>
> *package* test;
>
> *dialect* "mvel"
>
> *rule* "test 12"
>
>     *when*
>
>
>
>     *then*
>
>         *double* rightVal=(10 + 12);
>
>         *double* wrongVal=(10) + (12);
>
>         *double* wrongValTwo = ((10)+12)
>
>         System.out.println("Right "+rightVal);
>
>         System.out.println("Wrong "+wrongVal);
>
>        System.out.println("WrongTwo "+wrongValTwo);
>
> *End*
>
> * *
>
> *Results in:*
>
> Right 22.0
>
> Wrong 10.0
>
> WrongTwo 10.0
>
>
>
> Thanks,
>
> Joe
>
>
>
> *From:* rules-users-bounces at lists.jboss.org [mailto:
> rules-users-bounces at lists.jboss.org] *On Behalf Of *Edson Tirelli
> *Sent:* Wednesday, April 09, 2008 12:39 PM
> *To:* Rules Users List
> *Subject:* Re: [rules-users] Order of operations
>
>
>
>
>    Hi Joe,
>
>    It seems someone skipped the elementary math lessons at school... :(
>
>    Will open a JIRA for that.
>
>    []s
>    Edson
>
> 2008/4/9 Joe White <Joe.White at recondotech.com>:
>
> I have a question regarding order of operations in the consequence of a
> rule when using the mvel dialect. When executed the Drl below provides Right
> =30.0 and Wrong =140.0. The only difference is the parens around the
> multiplying expressions, which shouldn't be necessary given order of
> operations. Is this a problem with the drools/mvel interaction or is it
> completely an issue with mvel?
>
>
>
> Is the general expectation that all expressions must be completely scoped
> by parens when using mvel?
>
>
>
> *package* test;
>
> *dialect* "mvel"
>
> *rule* "test 11"
>
>     *when*
>
>
>
>     *then*
>
>         *double* rightVal=((10-5)*2) + (5*(8-4));
>
>         *double* wrongVal=(10-5)*2 + 5*(8-4);
>
>
>
>         System.out.println("Right ="+rightVal);
>
>         System.out.println("Wrong ="+wrongVal);
>
> *End*
>
> * *
>
> *After execution:*
>
> Right =30.0
>
> Wrong =140.0
>
>
>
>
>
> Thank you for all of your help. We are using drools 4.0.4.
>
>
>
> Joe
>
>
>
> Also, I haven't figured out how it arrives at 140. The following format
> also produces 140, which seems a little more strange.
>
>         *double* wrongVal=10-5*2 + 5*8-4;
>
>
>
>
>
>
>
>
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>
>
>
>
> --
> Edson Tirelli
> JBoss Drools Core Development
> Office: +55 11 3529-6000
> Mobile: +55 11 9287-5646
> JBoss, a division of Red Hat @ www.jboss.com
>
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>
>


-- 
Edson Tirelli
JBoss Drools Core Development
Office: +55 11 3529-6000
Mobile: +55 11 9287-5646
JBoss, a division of Red Hat @ www.jboss.com
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