[plt-scheme] V4 request for thoughts on various question

From: Sam TH (samth at ccs.neu.edu)
Date: Mon Aug 4 12:06:49 EDT 2008

On Mon, Aug 4, 2008 at 11:16 AM, Alan Watson <alan at alan-watson.org> wrote:
>>> The fact that let allow paralell bindings, do some folks take that
>>> fact and perform optimizations on multiple cpu boxes? Is it worth
>>> it?
>> The values are parallel, but the computation is not.  It's easy to
>> confuse the two, but it's a mistake.
> MPSCM[1] has a parallel let form.
> Eli, can you point me to language in the R5RS or R6RS that forbids
> interleaving the evaluation of the initializers in a standard let form? The
> R6RS just says, "The <init>s are evaluated in the current environment (in
> some unspecified order)". I think that allows the evaluation of the
> initializers to be interleaved or parallelized.

Looking at the R6RS, it appears that while the evaluation of arguments
may not be interleaved (the phrase is "consistent with some sequential
order"), that language is not used for `let'.  So I believe that the
evaluation of `let' bindings may be interleaved.

sam th
samth at ccs.neu.edu

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