title: Get old value of variable when setting new value
body: <pre><code>$variable = "hello";
  $variable = changevalue("world");
  
  function changevalue($newvalue) {
       if($variable == "hello") $variable = $newvalue;
  }
  </code></pre>
  
  <p>I know that is doable by &amp;. But, is there any way to get old value of variable without adding param &amp;$variable in changevalue?</p>