an class="identifier">date</span><span class="special">&gt;</span> <span class="identifier">weekends</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">discrete_interval</span><span class="special">&lt;</span><span class="identifier">date</span><span class="special">&gt;&amp;</span> <span class="identifier">scope</span><span class="special">)</span>
<span class="special">{</span>
    <span class="identifier">interval_set</span><span class="special">&lt;</span><sp