[Northy]

Apple has also hinted at technology that would allow developers to access Windows DLLs to rapidly port device drivers or other specialized software to the Mac with little effort. The ability to take foreign software, whether open or proprietary, for use in creating native Mac OS X apps offers a look at how Carbon apps can migrate their user interfaces to Cocoa, resulting in user interface consistency and other benefits for users while resulting in less code for developers to maintain.

Apple last year announced it would only be implementing a 64-bit Cocoa architecture, and not implementing a 64-bit Carbon architecture.
Developers who need a 64-bit user interface will need to use Cocoa. This line in the sand enables Apple to focus its resources on developing a single object-oriented user interface API for the 64-bit future. Developers such as Adobe and Microsoft will need to either stay in the past or move decisively into the future (See Adobe's CS4 suite, Microsoft Office etc.).

However, Apple plans to support and maintain the 32-bit Carbon Human Interface Toolbox well into the future, although it will not be adding any significant new features to those APIs. Snow Leopard will lead Carbon developers to Cocoa with carrots rather than just sticks - HICocoaView enables Carbon apps to add Cocoa features as an incremental step; Carbon apps will be required to adopt a Cocoa user interface entirely, and whilst doing so, Apple will encourage deveopers to consider adopting the Cocoa frameworks for other parts of their apps as well.

An example is Apple's own Finder in Leopard - largely a Carbon app, but it makes use of HICocoaView to embed Cocoa NSViews, such as when displaying CoverFlow. For Snow Leopard, the Finder would therefore apparently require building the entire user interface in Cocoa. Apple has indicated that will be happening in Snow Leopard. Therefore, the company is well aware of the effort needed to move to Cocoa, and is starting to lead by example.

There is still a murky area, neither Carbon, nor Cocoa it seems (Core Video, Quartz), amongst other things. So there is still work to be done on these areas too. Slowly raising the bar on what amount and parts of an app should be Cocoa at minimum, Apple is clearly pushing developers toward Cocoa. Meanwhile, Apple continues to support legacy code. Office 2004 was written as a PowerPC CFM app, which requires Apple to host it on top of CFMApp, which itself runs on top of Rosetta on Intel Macs. It will continue to work as expected in Snow Leopard. Anyone who likes to say that Apple “doesn’t support legacy” hasn’t looked too hard at what Apple has done to jump through hoops so Adobe and Microsoft wouldn’t have to bring their old code into the modern world.