Re: Unpack primitive types by default in data

On Thu, Feb 16, 2012 at 5:03 PM, Alex Mason wrote:

Of course, that makes sense. Do we already have a way to specify that a field should be lazy? I can imagine programs where we don't want this behaviour, and people would need an escape hatch (or their programs might run slower, or even not terminate). I know we've got lazy patterns with ~, do we have data Foo = Foo ~Int | Bar ~Double

This optimization would only apply for strict fields (otherwise it would be unsound.) There's already a NOUNPACK pragma in HEAD that lets you turn the optimization off. I think NOUNPACK was added both to support this feature and so one could turn off the effect of `-funbox-strict-fields` selectively. -- Johan