On 31 March 2006 13:41, John Meacham wrote:
I have tried to summarize the current thinking into a proposal on the wiki.
http://haskell.galois.com/cgi-bin/haskell-prime/trac.cgi/wiki/Concurrenc y
I split it into 3 parts.
the standard - all haskell' compilers must implement
optional preemption - ability to preempt pure code, fairness guarentees, interleaved evaluation operators (merge, nmerge)
optional OS threads - bound threads, SMP, reentrant concurrent FFI calls supported.
comment or modify it at will.
Great. Apart from my misgivings about allowing cooperative scheduling at all, here's a few comments on the proposal: - I wouldn't include threadWaitRead, threadWaitWrite, or threadDelay at all. These can all be implemented using FFI, so don't belong in the concurrency library. Their presence is largely historical. - yield bothers me a little. If it weren't for cooperative systems, yield would be semantically a no-op, because the no-starvation guarantee means you never need it for correctness. I think it's ok, just a bit unsettling. - In the optional OS threads section it says "allows multiple haskell threads to run at once" - actually you can provide all that without allowing multiple haskell threads to run at once, eg. ghc-6.4.1 with -threaded. I'll modify it. Cheers, Simon