Language ~ Why ActionScript 3
ActionScript and JavaScript are quite similar and were about to be consolidated and standardized as ECMAScript 4. The designated successor of JavaScript 1.x, implementing ECMAScript 4, is called JavaScript 2. Our first, more straight-forward approach was to implement an JavaScript 2-to-JavaScript compiler. But several trends made us rethink this approach:
- Because of Flex becoming really popular, tool support for AS3 is far better than for ES4 / JS2. This helps Jangaroo a lot, as we cannot and do not want to build all needed development tools on our own.
- There was no mutual consent in the ECMAScript committee and thus the next ECMAScript standard will not be fully compatible with ActionScript 3 ("ECMAScript Harmony"). On the one hand, it will contain many new language constructs not part of AS3, on the other hand, important AS3 language features like packages will not be part of ECMAScript for the time being.
- There is another project, Mascara, that concentrates on implementing ECMAScript 4, but without the focus on "programming in the large".
When having to decide, we thus chose to be compatible with ActionScript 3 rather than ECMAScript 4 / JavaScript 2. We consider "programming in the large" the main missing feature of today's JavaScript, and ECMAScript has decided to drop packages. ActionScript 3, however, has proven to offer all necessary features.
