pre class="literal-block">
typedef ... value_type;
typedef ... reference;
typedef ... const_reference;
typedef ... pointer;
typedef ... const_pointer;
</pre>
<p>However, the structure of the type mimics <tt class="docutils literal"><span class="pre">std::pair</span></tt> s.t. one
can use <tt class="docutils literal">first</tt> and <tt class="docutils literal">second</tt> members. The reference-types
are not real references and the pointer-types are not real pointers.
However, one may still write</p>
<pre cl