important news: refocusing discussion

Manuel M T Chakravarty chak at
Mon Mar 27 23:22:49 EST 2006

Simon Marlow:
> On 26 March 2006 03:44, Ross Paterson wrote:
> > On Sat, Mar 25, 2006 at 05:31:04PM -0800, isaac jones wrote:
> >> I have no idea if it would work, but one solution that Simon didn't
> >> mention in his enumeration (below) is that we could find a group of
> >> people willing to work hard to implement concurrency in Hugs, for
> >> example, under Ross's direction.
> > 
> > I'm no expert on Hugs internals, and certainly not qualified to direct
> > such an effort, but I don't have great hopes for it.  Apart from the
> > fact that Hugs is written in a legacy language and uses a quite a bit
> > of global state, it also makes heavy use of the C stack, and any
> > implementation that does that will have trouble, I think.
> Yes, I don't see an easy way to do it.  You could have one OS thread per
> Haskell thread (let the OS manage the separate C stacks), a giant lock
> around the interpreter (to protect all the global state), and explicit
> yield() from time to time to simulate pre-emption.  This isn't too bad,
> but you still have to implement GC somehow, and hence traverse all the
> live C stacks, and that sounds tricky to me.

True, but so what?  I mean, honestly, we should decide language features
by their merit to applications and maturity.  We should also take into
account what the power/weight ratio of a feature is in terms of general
implementation costs.  But discussing the costs to one particular
implementation that's already been stretched light years beyond what it
originally was intended for, seems a bit much.


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