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

From: Robby Findler (robby at cs.uchicago.edu)
Date: Mon Aug 4 12:33:24 EDT 2008

On Mon, Aug 4, 2008 at 11:06 AM, Sam TH <samth at ccs.neu.edu> wrote:
> 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.

Section 1.9 seems to be saying that let and the corresponding
left-left-lambda are equivalent.

For those that want to look it up, the text Sam quotes is at the end
of 9.1. This is what I was also referring to in my earlier message
(the one with the example let expression).


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