title: preg_replace() /e modifier is deprecated for HHVM
body: <p>I'm getting error with Symfony 1.4 <code>Deprecated: preg_replace(): The /e modifier is deprecated, use preg_replace_callback instead in /vagrant/lib/util/sfToolkit.class.php on line 365</code></p>
  
  <p>The function concerned is below:</p>
  
  <pre><code>public static function pregtr($search, $replacePairs)
    {
      if(strpos(implode(', ', $replacePairs),'e') &gt; 0)
        print_r($replacePairs);
  
      return preg_replace(array_keys($replacePairs),array_values($replacePairs), $search);
    }
  </code></pre>
  
  <p>The values concerned is:</p>
  
  <pre><code>Array
  (
      [#/(.?)#e] =&gt; '::'.strtoupper('\1')
      [/(^|_|-)+(.)/e] =&gt; strtoupper('\2')
  )
  </code></pre>
  
  <p>How can I change this to what is equivalent using <code>preg_replace_callback</code>?</p>