span class=identifier>iteration_policy
    </span><span class=special>{
        </span><span class=keyword>template </span><span class=special>&lt;</span><span class=keyword>typename </span><span class=identifier>ScannerT</span><span class=special>&gt;
        </span><span class=keyword>void
        </span><span class=identifier>advance</span><span class=special>(</span><span class=identifier>ScannerT </span><span class=keyword>const</span><span class=special>&amp; </span><span class=identifier>scan</span><