It would help if you read the documentation which explains that eval() must<br>return a boolean.<br><br>&quot;Predicate&quot; is a mathematical concept; how it is implemented in some system <br>is a technical issue. That said, &quot;predicates&quot; can be expressed in Drools one<br>
way or other, and some predicates may be more efficient than other, depending<br>on the computational details.<br><br>Again, the documentation contains many examples showing &quot;predicate&quot;<br>implementations, and usage of &quot;from&quot; is documented as well.<br>
<br>-W<br><br><br><div class="gmail_quote">On 20 April 2011 10:48, Arjun Dhar <span dir="ltr">&lt;<a href="mailto:dhar_ar@yahoo.com">dhar_ar@yahoo.com</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
I believe eval() solves that purpose functionally but is not optimal; not<br>
sure how evals() tie in with Rete-OO<br>
Specially since the return type of eval() is not known, I can seriously<br>
doubt it being optimal as using Objects directly in conditions.<br>
<br>
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