<?php

function functionFoo(&$var) {
  $var = "bar";
}

class Foo {
  function __construct() {
  }

  function doSomething() {
    $var = "foo";
    print $var . "\n";
    functionFoo($var);
    print $var . "\n";
  }
}

$foo = new Foo();
$foo->doSomething();

?>