 is active (that is, <TT>bab = true</TT>).
           Otherwise, you may define it as <TT>fun bound _ = assert false</TT>.
       </P>
    </DD>

    <DT>
      <TT><A name="compare">compare</A> <I>(solution1, solution2)</I></TT>
    </DT>
    <DD><P>Should return true if and only if <TT><I>solution2</I></TT> is better than <TT><I></I>solution1</TT>.</P>
        <P><B>Required</B>: This function is called only if
           <A href="sf-search.html#init">Search.init</A> or <A href="sf-search.html#betterThan"