<span class="identifier">E1</span><span class="special">,...&gt;</span> <span class="keyword">struct</span> <span class="identifier">composite_dimension</span><span class="special">&lt;</span><span class="identifier">DT1</span><span class="special">,</span><span class="identifier">E1</span><span class="special">,...&gt;;</span>

<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Dim</span><span class="special">,</span><span class