title: php call class function by string name
body: <p>How can I call a normal (not static) class function by its name?</p>
  
  <p>The below gives an error saying param 1 needs to be a valid callback. I don't want the function to be static, I want it to be a normal function, and all the examples I've seen so far had them static.</p>
  
  <pre><code>class Player
  {
      public function SayHi() { print("Hi"); }
  }
  
  $player = new Player();
  
  call_user_func($Player, 'SayHi');
  </code></pre>