ry allows to wrap types within round parenthesis so they can always
    be passed as macro parameters.
  </p><div class="section boost_utility_identitytype_motivation" title="Motivation"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="boost_utility_identitytype.motivation"></a><a class="link" href="#boost_utility_identitytype.motivation" title="Motivation">Motivation</a></h2></div></div></div><p>
      Consider the following macro which declares a variable named <code class="