rong></span>: Returns the starting location of
        sub-expression <span class="emphasis"><em>sub</em></span>, or -1 if <span class="emphasis"><em>sub</em></span>
        was not matched. Note that if this represents a partial match , then <code class="computeroutput"><span class="identifier">position</span><span class="special">()</span></code>
        will return the location of the partial match even though <code class="computeroutput"><span class="special">(*</span><span class="keyword">this</span><s