Apple aren’t making a “transition” to Ruby, but they are paving a way to better support it. It is, as you say in your comment, on track to become “a first-class citizen.” It will not be a replacement.

Onwards and upwards, though. I love Ruby (sorry, MikeFM).

We don’t know their commitment to it, but it’s a closer connection than just “Apple uses LLVM and Ruby uses LLVM”, it’s more accurately “Apple is using LLVM to implement Ruby”, which is a much stronger statement.

It can be argued that MacRuby will allow you to more easily take advantage of blocks and GCD, with built in generational garbage collection without the verbosity of ObjC or the ambiguity the dot implementation of ObjC either for those that prefer dot notation.

I’m not a language designer but….
Blocks and lambdas are interesting and valuable language features in and of themselves. They allow for a more functional and ultimately more declarative style of coding, probably regardless of the language in which they are implemented. I imagine it was these notions, and not the idea that it would aid language developers, that were taken into account when the Block specification introduced.

Incidentally, the statement that blocks “would be required to implement to support Ruby blocks and lambda functions”, is just silly. MRI Ruby is implemented in C, no? Standard C has no notion of lambdas, blocks, or closures. The closest language construct would probably be a function pointer. That appears to be enough.