perator will match the
        preceding atom <span class="emphasis"><em>one or more times</em></span>, for example the expression
        a+b will match any of the following:
      </p>
<pre class="programlisting">ab
aaaaaaaab
</pre>
<p>
        But will not match:
      </p>
<pre class="programlisting">b
</pre>
<p>
        The <code class="computeroutput"><span class="special">?</span></code> operator will match the
        preceding atom <span class="emphasis"><em>zero or one times</em></span>, for examp