 =&gt; \$dest_string,
      stderr      =&gt; \$stderr_string,
      errorfile   =&gt; \$errorfile_string,  # ignored when -se flag is set
      ##phasers   =&gt; &#39;stun&#39;,              # uncomment to trigger an error
  );

  if ($error) {

      # serious error in input parameters, no tidied output
      print &quot;&lt;&lt;STDERR&gt;&gt;\n$stderr_string\n&quot;;
      die &quot;Exiting because of serious errors\n&quot;;
  }

  if ($dest_string)      { print &quot;&lt;&lt;TIDIED SOURCE&gt;&gt;\n$dest