title: What is a good test case showing the regex performance problems of the pre/post/match vars in Perl?
body: <p>In the <code>English</code> module and a few other places, users are advised never to use the <code>$&amp;</code> <code>$`</code> and <code>$'</code> variables or their <code>English</code> equivalents <code>$MATCH $PREMATCH $POSTMATCH</code> due to the fact that they will slow down all regex use.</p>
  
  <p>What is a good test case (benchmark) that shows the performance problems?</p>