an> <span class="keyword">return</span> arg<span class="special">; 
      }</span> <span class="comment">// return the argument arg</span><br>
      </code><br>
      Meta-functions are essentially the same. These beasts also accept arguments 
      and return a result. However, while functions work at runtime on values, 
      meta-functions work at compile time on types (or constants, but we shall 
      deal only with types). The meta-function is a template class (or struct). 
      The template paramete