      s.foreach(v) =&gt;
         if $(equal $(v), 0)
            count = $(add $(count), 1)
            export
         export
      return $(count)
   </PRE></LI><LI CLASS="li-itemize"><CODE>$(s.forall &lt;fun&gt;)</CODE>: tests whether each element of the sequence
satifies a predicate.
</LI><LI CLASS="li-itemize"><CODE>$(s.exists &lt;fun&gt;)</CODE>: tests whether the sequence contains an element
that satisfies a predicate.
</LI><LI CLASS="li-itemize"><CODE>$(s.sort &lt;fun&gt;)</CODE>: sorts a sequence.