dex.html" target="_top">Boost.Lambda</a>, or
            <a href="../../../../../../../libs/phoenix/doc/html/index.html" target="_top">Boost.Phoenix</a>.
            The latter three allow you to use special placeholders to control parameter
            placement (<code class="computeroutput"><span class="identifier">_1</span></code>, <code class="computeroutput"><span class="identifier">_2</span></code>, etc.). Each of those libraries
            has it's own implementation of the placeholders, all in diff