et another domain. Yet, all these can potentially share
          the same placeholders for interoperability. The interpretation of these
          placeholders is domain-specific.
        </p>
<p>
          Now that we enabled the placeholders, we have to write generators for them.
          The make_xxx stuff (in boost::spirit::qi namespace):
        </p>
<p>
</p>
<pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span>
    <span class="keyword">typename</span> <