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@lists.jboss.org
[mailto:rules-users-bounces@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@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
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