Xcode 4.4, which is currently a developer preview for Mountain Lion (Mac OS X 10.8) will contain the llvm 4.0 compiler.
There’s a few nifty things in that compiler, such as number literals, collection literals, and object subscripting. Here’s clang documentation about the new features.
Very nice things. Are they totally necessary? No, we’ve gotten along without them for this long. But the syntactical sugar is welcome as it will make it easier to write code. Plus depending just what feature we’re talking about and how it’s implemented, good can come from it (e.g. how the object subscripting is implemented).
I haven’t looked at the developer preview yet, only been able to read about it. I’ll be curious to see how this affects iOS development, since it seems obvious this requires not only compiler support but some changes to the OS as well.