If you need to get a reference to a class in ActionScript 3, but only know the class name, then you can use the flash.utils.getDefinitionByName to create an instance of the class.
public class DynamicCall extends Sprite
public function DynamicCall()
var ClassReference:Class = getDefinitionByName("String") as Class;
var s:String = (new ClassReference("foo=") as String);
This basically creates an instance of the String class, from the class name “String”. getDefinitionByName takes the entire class path, so if you wanted to create an instance of MovieClip, you would provide the entire path:
var ClassReference:Class = getDefinitionByName("flash.display.MovieClip") as Class;
Anyways, pretty simple stuff, but can come in useful.