title: Use templates as a members when not all the details are known
body: <p>Is it possible to specifiy a template as a member but not know all the details? Or rather how can I work around this.</p>
  
  <p>Example doesn't work but might show you what I'm trying to achieve. </p>
  
  <pre><code>template&lt;typename T&gt;
  struct Foo {
     ///blah...
  };
  
  struct Bar {
      Foo* m_foo;
  };
  </code></pre>
  
  <p><code>Bar</code> in this case is a base class, and depending on the derived classes I wont know the full details of <code>Foo</code></p>