We just published version 0.09 of the Dart Language Spec.
- Abstract methods may specify default values.
- Interface methods may specify default values.
- The ~/ operator can apply to doubles.
- Refined rules regarding abstract class instantiation, allowing factories to be used.
- switch statement specification revised.
- throw may not throw null.
- Imports introduce a scope separate from the library scope. Multiple libraries may share prefix.
- Recursive typedefs disallowed.
The switch statement now requires either all the expressions in the cases to evaluate to constant integers or they all evaluate to constant strings. Also, a warning can be generated if you omit the break statement in a case.
As always, the Dart mailing list is standing by to answer your questions, and dartbug.com is a good way to file bugs and feature requests.