n unknown number
        category (because <code class="computeroutput"><span class="identifier">number_category</span></code>
        is not specialised for that type) then this trait will be <code class="computeroutput"><span class="keyword">true</span></code>.
      </p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">From</span><span class="special">,</span> <span class="keyword">typename</sp