fier">_context</span><span class="special">)</span>
              <span class="special">&gt;</span>
          <span class="special">&gt;</span>
    <span class="special">{};</span>
<span class="special">};</span>
</pre>
<p>
        Wow, this looks complicated! Granted you need to know a little bit about
        <a href="http://www.boost.org/doc/libs/release/libs/proto/index.html" target="_top">Boost.Proto</a>
        (For a good introduction read through the <a href="http://cpp-next.com/archive/2010/08/expr