important news: refocusing discussion

Manuel M T Chakravarty chak at
Fri Mar 24 15:25:46 EST 2006

Simon Marlow:
> On 24 March 2006 12:28, Ross Paterson wrote:
> > 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. 
> This is just a difference of opinion, and probably won't be easily
> resolved.  It comes down to whether you think Haskell' should be a
> language that is wide enough to include such applications as a web
> server, or whether it has to stop short of including concurrency because
> it's too hard to implement (and it's not always hard - the YHC guys
> managed it in a matter of days, but I do realise it would be hard in
> Hugs).
> I think it would be a mistake to relegate concurrency to an addendum; it
> is a central feature of the language, and in fact is one area where
> Haskell (strictly speaking GHC) is really beginning to demonstrate
> significant advantages over other languages.  We should make the most of
> it.

I 100% agree!!  Personally, I think, after the FFI, a good story about
concurrency and exceptions is what H98 misses most for applications
other than variations on the compiler theme.


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