title: Specialize template functor over template class
body: <p>Let's say I have a template functor :</p>
  
  <pre><code>template &lt;class U, class V&gt;
  struct Converter
  {
      V&amp; operator() (const U&amp;, V&amp;) const;
  };
  </code></pre>
  
  <p>I want to "specialize" this converter over a template class and a non-template class :</p>
  
  <pre><code>template&lt;&gt;
  struct Converter &lt;template&lt;class&gt; MyTemplateClass, MyNonTemplateClass&gt;
  {
      //I can't use MyTemplateClass without specializing it 
      //even if I don't need it to perform the computation
  };
  </code></pre>
  
  <p>Of course, this can't work. How would you do to achieve a similar result ?</p>