iPhone 0S 4.0 - Impact on developers

The recent announcement of iPhone OS 4.0 is very exciting for consumers. There are a number of new features that have been long awaited (e.g., multitasking, single threaded email, etc...) and will have a significant impact on the end-user experience.

There is also a significant feature that will seemingly have a significant impact on developers. Apple has included new language in the in the 4.0 developer license agreement. The key point is that Apple mandates that now:

Applications must be originally written in Objective-C, C, C++, or JavaScript as executed by the iPhone OS WebKit engine, and only code written in C, C++, and Objective-C may compile and directly link against the Documented APIs (e.g., Applications that link to Documented APIs through an intermediary translation or compatibility layer or tool are prohibited).

The significance of this new language is that a number of 3rd party tools appear to possibly be locked out of the iPhone 4.0. The biggest target would seem to be the soon-to-be-released Adobe Flash CS5 which includes the Flash Packager for iPhone. This language potentially blocks Apps created with that tool from released to iPhone 4.0. However, this language has implications for any number of similar tools including popular game engines such as Unity3D and Torque.

An important question is why the change? Macworld suggests that it's primarily a play to block Adobe from the iPhone platform:
Macworld article

The folks at Apple Insider have a different take, suggesting that the change stems from a necessity to enforce the use of Apple tools to ensure smooth multitask operation. Apple Insider article