Re: Unpack primitive types by default in data

On 17/02/2012, at 17:51, Johan Tibell wrote:

On Fri, Feb 17, 2012 at 12:52 AM, Roman Leshchinskiy wrote:

...

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.

Ok, that makes sense. I would include Double# and Int64# in this list. For the simple reason that if the target audience are beginners they will have a hard time figuring out why their programs run 20x faster with Float/Int than with Double/Int64 instead of just 2x faster. Roman