Migrating from ActionScript 2.0 to ActionScript 3.0 is as much a matter of following subtle changes in the development of the language as learning new features. In many cases, all you’ll need to do to upgrade a script, you just have to change a class name or, perhaps, change from a method to a property. These kinds of changes are typically easy to identify because you need minor adjustments. In other cases, however, you may find yourself searching for missing functionality. Like looking up an unfamiliar word in the dictionary, you need a place to start.
This chapter is essentially a cross-reference to material covered elsewhere in this book, but also includes additional material not otherwise discussed. The primary goal is to help you find something you used in ActionScript 2.0 but appears to be missing or significantly changed in ActionScript 3.0.
Itemizing every change introduced by ActionScript 3.0 is beyond the scope of this book. However, you can find a concise, table-based guide called “ActionScript 2.0 Migration” in the Help system by searching for “migration” or by looking online at http://livedocs.adobe.com/flex/2/langref/migration.html. While this table doesn’t include examples, it does point you to the correct new Help entry in ActionScript 3.0 syntax, if one exists.
When you know specifically what to look for, and in which package or class to look, the Help table is probably the best place to start. However, you can ...