[rules-users] Issues Regarding use " Eval"

[Miguel Figueiredo]

I had problems with this too, I will use this tip :]

Evals really suck. I tried to load simples rules with eval, and I couldn't get 
past 3000 rules. Without evals I loaded 15000.

On Monday 02 July 2007 18:00, Edson Tirelli wrote:
>    Eval's are indeed less performatic than any other type of constraints.
> "inline-evals" are not as bad, but are also heavier than regular
> constraints.
>    The recommendation is to avoid when possible, but for some cases it is
> not possible.
>
>    If you are using MR3 or later, you can use MVELs syntax in your
> constraints:
>
> when
>    MyClass( aMapAttribute['aKey'] == "some Value" )
> then
>    ...
> end
>
>     The above will transparently be translated to an inline-eval, but that
> is the best you can do when working with maps.
>
>     []s
>     Edson
>
> 2007/7/2, Rajesh_Kumar <Rajesh_Kumar at rsystems.com>:
> > Hi all,
> >
> > I want to use "eval" in my rules, but in rule writing guidelines Mark
> > has
> > Written that "Eval is Evil".
> >
> > I want to compare the values of Hash Map in my when (conditions) part.
> >
> > 1) Will anyone suggest something so that I can compare Hash Map keys in
> > when part?
> >
> > 2) Does is there any performance related issue related to "eval";
> >
> > Regards
> >
> > Rajesh
> >
> > --
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