span class="identifier">identity_d</span><span class="special">(</span><span class="number">1.23</span><span class="special">)</span> <span class="special">==</span> <span class="number">1.23</span><span class="special">);</span>
</pre>
<p>
    </p>
<p>
      It is possible to use this library to create a single <a href="http://en.wikipedia.org/wiki/Function_overloading" target="_top">overloaded</a>
      function object (or <a href="http://en.wikipedia.org/wiki/Functor" target="_top">functor</a>)
      nam