n class="special">}</span>
    <span class="special">}</span>

<span class="keyword">private</span><span class="special">:</span>
    <span class="keyword">mutable</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">format</span> <span class="identifier">m_format</span><span class="special">;</span>
<span class="special">};</span>

<span class="comment">// Custom point formatter factory</span>
<span class="keyword">class</span> <span class="identifier">point_f