title: how to call member functions when the objects is variable template parameters
body: <p>how to call member functions when the objects is variable template parameters? Here's a example:</p>
  
  <pre><code>template &lt;typename ...A&gt;
  void f(A... args)
  {
      args-&gt;memfunc("examples")...; // the code not right!
  }
  </code></pre>
  
  <p>How to do it right?</p>