title: preg_match_all won't match this pattern
body: <pre><code>preg_match_all("/&lt;td&gt;\d{4}/i", $a, $b);
  </code></pre>
  
  <p>does not match</p>
  
  <pre><code>&lt;td&gt;dddd
  </code></pre>
  
  <p>whereas</p>
  
  <pre><code>preg_match_all("/\d{4}/i", $a, $b);
  </code></pre>
  
  <p>works just fine.</p>
  
  <p>Am I missing something?</p>