On Fri, Feb 17, 2012 at 12:52 AM, Roman Leshchinskiy
I'm not convinced that this is a good idea because it doesn't treat all types equally. The comparison with Java is problematic, IMO, because in Java 'int' is always called 'int' whereas in Haskell, it might be called many different things.
To better understand the proposal, which of the types below would you want to be unboxed automatically?
data A = A Int# newtype B = B A data C = C !B data D = D !C data E = E !() data F = F !D
All of the above. Put in other words: all fields whose final representation type could be the size of a pointer if we unpacked enough. Note that the user only needs to understand when unpacking happens if he/she wants to reason about whether a given strict field will be automatically unpacked. When in doubt he/she can always use an explicit UNPACK or NOUNPACK. We're trying to make the default case more sane, not remove control. -- Johan