title: PHP PCRE error preg_replace
body: <pre><code>&lt;?php
      function pregForPreg($value)
      {
          $value = preg_replace(array('#\(#', '#\)#', '#\+#', '#\?#', '#\*#', '#\##', '#\[#', '#\]#', '#\&amp;#', '#\/#', '#\$#', '#\\\\#'), array('\(', '\)', '\+', '\?', '\*', '\#', '\[', '\]', '\&amp;', '\/', '\\\$', '\\\\'), $value);
          return $value;
      }
  
      $var = "TI - Yeah U Know [OFFCIAL VIDEO] [TAKERS] [w\LYRICS]";
  
      $var = pregForPreg($var);
      //$var is now:
      //    TI - Yeah U Know \[OFFCIAL VIDEO\] \[TAKERS\] \[w\LYRICS\]
      $var = preg_replace("#" . $var . "#isU", 'test', $var);
      echo $var;
  </code></pre>
  
  <p>And I get an error: *Warning: preg_replace(): Compilation failed: PCRE does not support \L, \l, \N, \U, or \u at offset 50 in <strong>test.php</strong> on line 13.*</p>
  
  <p>How to make a correct function pregForPreg?</p>