 The <CODE>&lt;fun&gt;</CODE> is a comparison
function. It takes two elements <CODE>(x, y)</CODE> of the sequence, compares them, and returns
a negative number if <I>x</I> &lt; <I>y</I>, a positive number if <I>x</I> &gt; <I>y</I>, and zero if the two elements
are equal.<PRE CLASS="verbatim">  osh&gt; items = $(int 0 3 -2)
  osh&gt; items.forall(x =&gt; $(gt $x, 0))
  - : bool = false
  osh&gt; items.exists(x =&gt; $(gt $x, 0))
  - : bool = true
  osh&gt; items.sort($(compare))
  - : Array = -2 3 0
  </PRE>