pan class="special">(</span><span class="keyword">const</span> <span class="identifier">mpl</span><span class="special">::</span><span class="identifier">int_</span><span class="special">&lt;</span><span class="number">0</span><span class="special">&gt;&amp;)</span>
            <span class="special">{</span>
              <span class="keyword">return</span> <span class="identifier">tools</span><span class="special">::</span><span class="identifier">digits</span><span class="special">&lt;</span><span class="