ace is slightly changed towards the domain of pointers
instead of relying on the normal value-based interface. For example,
now it is possible for <tt class="docutils literal"><span class="pre">pop_back()</span></tt> to return the removed element.</li>
</ol>
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<ol class="arabic simple" start="7">
<li>Propagates constness such that one cannot modify the objects via a <tt class="docutils literal"><span class="pre">const_iterator</span></tt>.</li>
</ol>
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<ol class="arabic simple" start="8">
<l