">ref</span></code></a>(c), <a href="http://www.boost.org/libs/core/ref.html" target="_top"><code class="computeroutput"><span class="identifier">ref</span></code></a>(d)) <a href="#ftn.fusion.container.generation.functions.tiers.f0" class="footnote" name="fusion.container.generation.functions.tiers.f0"><sup class="footnote">[11]</sup></a>.
          </p>
<p>
            A <span class="emphasis"><em>tie</em></span> can be used to 'unpack' another tuple into
            variables. E.g.:
          </p>
<pre c