title: Why can't typed optional arguments have a default of Null?
body: <p>In ActionScript 3, when you declare an optional argument by giving it a default value, the value <strong>null</strong> cannot be used on typed arguments.</p>
  
  <pre><code>function Action(Param:int=null){
      // 1184: Incompatible default value of type Null where int is expected.
  }
  function Action(Param:int=0){
      // No compiler errors
  } 
  </code></pre>
  
  <p>Any workarounds for this, or general purpose values that can apply to all data types?</p>