Tabs have been outlawed since they are treated differently by different editors and tools. And since indentation is so critical to proper interpretation of YAML, this issue is just too tricky to even attempt. Indeed Guido van Rossum of Python has acknowledged that allowing TABs in Python source is a headache for many people and that were he to design Python again, he would forbid them.

(Source: yaml.org)

MacRuby has been looking increasingly interesting lately as Laurent Sansonetti at Apple has rapidly built it into a quite performant, stable implementation. It runs on LLVM and is being included with XCode 4/Lion. Lion itself is switching heavily to LLVM, which almost certainly means iOS 5 will as well. The big question for WWDC is whether iOS 5 will get garbage collection, which looks to be the only remaining roadblock for MacRuby on iOS.

(Source: pogodan.com)