special">,</span> <span class="identifier">MaxDigits</span><span class="special">&gt;</span> <span class="identifier">result_type</span><span class="special">;</span>
    <span class="identifier">result_type</span> <span class="keyword">operator</span><span class="special">()(</span><span class="identifier">unused_type</span><span class="special">,</span> <span class="identifier">unused_type</span><span class="special">)</span> <span class="keyword">const</span>
    <span class="special">{</span>
        <s