 the rule.  The rule will be fired if and only if the s-expression is true.</p>
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<div class="paragraph">
<p>Predicate rules do not need to have a phase specified.  If a phase is specified, the rule is fired only in that phase.  If no phase is specified, the rule will fire in the earlier phase in which the s-expression is true.</p>
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<div class="paragraph">
<p>Predicate rules should not depend on targets or operators: they should always fire.  In Waggle, use the <code>Predicate</code> rule type.  