title: How to convert Haxe Array/Vector to another type
body: <p>Let's say I've got an array or vector of some parent type. To pass it to a function, I need it to be some child type (which I know beforehand that all elements are guaranteed to be all that child type). Is there a convenient way to do that?  Right now I can only think to make a whole new array.</p>
  
  <p>Also, it looks like it won't let me do it the other way around: it won't accept an array of child type in the place of the parent type.  Is there a good way to solve this situation as well?</p>
  
  <p>It looks like <code>cast v</code> works, but is this the preferred way?</p>