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;