title: PHP call_user_func vs. just calling function
body: <p>I'm sure there's a very easy explanation for this.  What is the difference between this: </p>
  
  <pre><code>function barber($type){
      echo "You wanted a $type haircut, no problem\n";
  }
  call_user_func('barber', "mushroom");
  call_user_func('barber', "shave");
  </code></pre>
  
  <p>... and this (and what are the benefits?):</p>
  
  <pre><code>function barber($type){
      echo "You wanted a $type haircut, no problem\n";
  }
  barber('mushroom');
  barber('shave');
  </code></pre>