@pserranne: I am glad you like it! Please let us know if you want us to drill deeper into any specific aspects.
@sokhaty: User-defined Aggregators are available now (that part of the documentation needs still to be written, thanks for reminding me :)). However they cannot be used in the context of windowing expressions. Please go to
to file a request. Do you need user-defined aggregators with windowing expression? User-defined ranking or user-defined analytics functions? Some of them are on our backlog but at a lower priority right now.
We are currently working on a local development experience inside VisualStudio (for now) that will provide local running of U-SQL, local debugging of server failures and more. However I would not call it an emulator (emulator implies some heavy weight installation requirement that we want to avoid) :).