Multiple Returns, was Re: Common Lisp style macros in
Smalltalk?
Alan Knight
knight at acm.org
Thu Jan 27 16:11:39 UTC 2000
At 08:18 AM 27.01.2000 -0500, Vassili Bykov wrote:
> > From: demiourgos at smalltalk.org [mailto:demiourgos at smalltalk.org]
> > But I have wondered from time to time -- not having deep process-based
> > experience in Smalltalk (applications instead) -- how one might go about
> > implementing coroutines or continuations in the manner of Scheme. Or
> > are these things too far out of the Smalltalk model?
>
>I implemented continuations for Squeak a couple of year ago. Nobody seemed
>particularly impressed, so even if they are not far out of the Smalltalk
>implementation, they are far out of the Smalltalk thinking.
>
>--Vassili
Blocks with returns in Smalltalk are pretty close to passing continuations,
and so the typical Smalltalk thinking would probably be to use blocks for
these purposes. I know I find it easier to think in those terms than in
terms of continuation-passing. Once upon a time, Anthony Lander and Jon
Hylands implemented a Prolog in Smalltalk using this kind of technique. It
passed blocks within blocks within blocks around, and backtracking was
implemented through block return.
--
Alan Knight [|] knight at acm.org
The Object People 613.225.8812(v) 613.225.5943(f)
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