From: brbarkstrom@gmail.com
Subject: Re: Asynchronicity and Promises
Date: Thu, 29 Oct 2015 05:38:36 -0700 (PDT)
Date: 2015-10-29T05:38:36-07:00 [thread overview]
Message-ID: <597832aa-6b77-40ac-a0db-ce43be348299@googlegroups.com> (raw)
In-Reply-To: <1qrjm5vaptsw$.14uwmxveagjrt$.dlg@40tude.net>
On Wednesday, October 28, 2015 at 2:46:37 PM UTC-4, Dmitry A. Kazakov wrote:
>
> > There's an interesting blog on Asynchronicity and Promises at
> [...]
> > I think we've had some discussion in other e-mail threads here.
> > As far as I've been able to follow the discussion, we don't seem
> > to have settled the issue about how Ada could handle contract
> > "Promises" - although it looked like we had begun to converge
> > on some useful potential approaches.
>
> Ada had this since Ada 95 in the form of a protected object. Protected
> object's state is waitable. That gives you everything you need to design
> things described. They are not 100% asynchronous because the caller waits
> for the callee at some point anyway.
>
> As a side note, usefulness of this approach is questionable. I can judge,
> because this sort of objects and asynchronous execution has been used in
> the middleware for 20+ years. A lot of use cases to be sure. It is
> certainly neither natural nor composable and works at the low level only.
> To be honest, I know no better way, but you must clearly understand
> limitations of the approach, e.g. a total lack of scalability. Ada's
> concurrency model has much more to offer and at the higher level as well.
>
> P.S. What wonders me is that the author is seemingly unaware of 30+ years
> of OS having asynchronous I/O and waitable objects. Just google for Windows
> GetOverlappedResult.
>
> --
Thanks for the response. I'll take a look.
Bruce B.
prev parent reply other threads:[~2015-10-29 12:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-28 15:33 Asynchronicity and Promises brbarkstrom
2015-10-28 18:46 ` Dmitry A. Kazakov
2015-10-29 12:38 ` brbarkstrom [this message]
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