span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Expr</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Delimiter</span><span class="special">&gt;</span>
    <span class="keyword">inline</span> <span class="special">&lt;</span><span class="identifier">unspecified</span><span class="special">&gt;</span>
    <span class="identifier">format_delimited</span><span class="special">