title: Setting default value for function argument in actionscript 3
body: <p>Is there any way that I can reference a var or const as the default value for a function argument in actionscript 3.</p>
  
  <p>I can define default values like null, string, int.</p>
  
  <pre>function a( b = null ) {
     blah...
  }</pre>
  
  <p>But what I want to do is <pre>function a( b = function(){} ) {
      blah...
  }</pre></p>
  
  <p>which it seems like there would be a way to do.  Presumably through a const</p>