</span><span class="special">::</span><span class="identifier">accumulators</span><span class="special">::</span><span class="identifier">depends_on</span><span class="special">&lt;</span><span class="special">&gt;</span>, <span class="keyword">public</span> <span class="identifier">rolling_window_size</span>
<span class="special">{</span>

  <span class="comment">// public data members</span>
  <span class="keyword">static</span> <span class="identifier">boost</span><span class="special">::</span><span cla