re is no <tt class="docutils literal">index</tt> parameter in
the <span class="concept">ArgumentPack</span>, <tt class="docutils literal">42</tt> will be used instead.</p>
<p>Now we are ready to write the parameter-enabled constructor
interface:</p>
<pre class="literal-block">
struct myclass : myclass_impl
{
    BOOST_PARAMETER_CONSTRUCTOR(
        myclass, (myclass_impl), tag
      , (required (name,*)) (optional (index,*))) // no semicolon
};
</pre>
<p>Since we have supplied a default value for <tt class=