DDC compiler and effects;
better than Haskell? (was Re: [Haskell-cafe] unsafeDestructiveAssign?)
John A. De Goes
john at n-brain.net
Sun Aug 16 09:50:43 EDT 2009
On Aug 15, 2009, at 5:32 PM, Sebastian Sylvan wrote:
> On Sun, Aug 16, 2009 at 12:18 AM, John A. De Goes <john at n-brain.net>
> You must think I'm arguing for some kind of low-level analog of C,
> augmented with an effect system. I'm not. You can't do that.
> No, I don't. I think you're arguing for making access to mutable
> state commutative. Are you not?
There are many cases when mutation to state _is_ commutative. I can't
argue that certain operations are _always_ commutative without talking
about the language.
Pretend I'm arguing for a mostly functional language and effect system
that maximize the opportunities for parallelizing code.
> I'm not saying you shouldn't parallelise them in very specific
> circumstances *where it's safe*, I'm just saying that you shouldn't
> assume that it's safe unless you know it is. If you want to do a
> transformation that's unsafe in general, but safe in a specific
> circumstance, then of course, go ahead!
> To my reading it seems like you're arguing that memory/file access
> should *always* be considered commutative though, which is what I'm
> objecting too.
In the right language, many times of memory (and possibly file)
operations _always_ commute. In the wrong language, they _sometimes_
commute or _never_ provably commute. I'm not arguing for the
assumption in any language where it is false.
John A. De Goes
The Evolution of Collaboration
http://www.n-brain.net | 877-376-2724 x 101
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