 class="computeroutput"><span class="identifier">iterator_adaptor_</span></code>
          type that refers to itself, that gives us a convenient way to refer to
          the complicated base class type of <code class="computeroutput"><span class="identifier">node_iter</span><span class="special">&lt;</span><span class="identifier">Value</span><span class="special">&gt;</span></code>. [Note: this technique is known not
          to work with Borland C++ 5.6.4 and Metrowerks CodeWarrior versions prior
     