title: array_walk or array_map?
body: <p>I'm currently using <code>array_map</code> to apply callbacks to elements of an array. But I want to be able to pass an argument to the callback function like <code>array_walk</code> does.
  I suppose I could just use <code>array_walk</code>, but I need the return value to be an array like if you use <code>array_map</code>, not TRUE or FALSE.</p>
  
  <p>So is it possible to use <code>array_map</code> and pass an argument to the callback function? Or perhaps make the <code>array_walk</code> return an array instead of boolean?</p>