ypes, does not generate an error,
          and the macro in which it is being used does generate some output, it is
          necessary to use BOOST_PP_CAT to concatenate the empty result of the VMD
          ASSERT macro with the normally generated output to correctly generate the
          final expansion of the macro in which the VMD ASSERT occurs.
        </li>
<li class="listitem">
          When using BOOST_VMD_EMPTY following some non-empty expansion, or when
          using BOOST_VMD_IDENTITY, the 