ss=special>,</span><span class=keyword>int</span><span class=special>,&amp;</span><span class=identifier>employee</span><span class=special>::</span><span class=identifier>ssnumber</span><span class=special>&gt;</span> <span class=special>&gt;</span>
  <span class=special>&gt;</span>
<span class=special>&gt;</span> <span class=identifier>employee_set</span><span class=special>;</span>
</pre></blockquote>

<p>
the second and third indices use <code>member</code> extractors on
<code>employee::name</code> and 