title: Syntax error while using yield with PHP5.4
body: <p>I was trying to get yield working and I copied and pasted the following code from <a href="http://php.net/manual/en/language.generators.syntax.php" rel="nofollow">http://php.net/manual/en/language.generators.syntax.php</a> into an empty file and got the error Parse error: syntax error, unexpected '$i' (T_VARIABLE) in [FILENAME]</p>
  
  <p>I'm running XAMPP v3.2.1 which has been working perfectly for the rest of my code (haven't used a yield statement yet) and PHP 5.4.16.</p>
  
  <p>Any idea what I'm doing wrong or what I should do?</p>
  
  <pre><code>&lt;?php
  function gen_one_to_three() {
      for ($i = 1; $i &lt;= 3; $i++) {
          // Note that $i is preserved between yields.
          yield $i;
      }
  }
  
  $generator = gen_one_to_three();
  foreach ($generator as $value) {
      echo "$value\n";
  }
  ?&gt;
  </code></pre>
  
  <p>the code has no error if you replace yield with echo</p>