Concurrency (was: RE: Re[2]: important news: refocusing discussion)

[Malcolm Wallace]

"Simon Marlow" <simonmar at microsoft.com> wrote:

>  (a) we're going to standardise concurrency anyway

Well, but that only begs the question, what *kind* of concurrency are we
going to standardise on?  e.g. Will we admit all variations of scheduling
(co-operative, time-slice, and pre-emptive)?

>  (b) it is unlikely that Hugs or JHC will implement concurrency
>      even if it goes into the standard

Now this is something that puzzles me.  I was under the impression that
Hugs already implements concurrency, using pretty much the same APIs as
ghc.

I'd also like to know a bit more about jhc's position here.  Is it just
that JohnM wants to keep his compiler "pure" and free from having a
runtime-system?  Or are there other issues?

> Yes there are several ramifications of this decision, but none of them
> are technical.  As I see it, we either specify Concurrency as an
> addendum, or NoConcurrency as an addendum, and both options are about
> the same amount of work.

There are certainly technical questions.  If Hugs's implementation of
concurrency is not concurrency after all, on what basis do we make that
determination?  Why is a definition of concurrency that encompasses both
ghc and Hugs models unacceptable?

Regards,
    Malcolm