On Fri, Mar 24, 2006 at 11:30:57AM -0000, Simon Marlow wrote:
So I believe the issue is mainly one of perspective. Until I wrote this email I hadn't thought of (4) and my preference was for (2), but now I quite like the idea of (4). We would include concurrency in Haskell', but provide a separate addendum that specifies how imlementations that don't provide concurrency should behave. One advantage of (4) over (3) is that we can unambiguously claim that Haskell' has concurrencey.
And we can unambiguously state that there is only one Haskell' implementation (though a second is on the way). Sure, concurrency is essential to many applications, and should be precisely specified. But it is also irrelevant to a lot of uses of Haskell (except for ensuring that one's libraries are also usable on concurrent implementations, as JohnM said). A specification of the language without concurrency would be at least as valuable (having more implementations). Perspective, as you say -- most people agree we need both -- but I think you're a bit too negative about the smaller variant.