title: passing a function name as parameter in LUA
body: <p>So I have a button class in which I create my button:</p>
  
  <pre><code>self.button = widget.newButton {..., onEvent = handleEvent)
  </code></pre>
  
  <p>And I want to call that button class in my main, so i'm doing :</p>
  
  <pre><code>local button = Button:new(..., handle)
  </code></pre>
  
  <p>The thing is all my event handler are located in my button class.
  How can i pass the name of the event handler from outside the class ? </p>
  
  <p>I can't just pass it as handle neither as "handle" ...
  I guess I would have to pass it as a function, but how can I do that ?</p>