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Re: Always using let*

From: Stefan Monnier
Subject: Re: Always using let*
Date: Mon, 15 Sep 2014 08:31:35 -0400
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4.50 (gnu/linux)

> But if you have side-effect free expressions, (or at least, provably
> independent ones), then they could be evaluated in parallel despite the
> left-to-right rule.

Same holds for let* or pretty much anything else for that matter: if
some analysis can prove that it can be done in parallel, well, then
unsurprisingly it can be performed in parallel.  But it's not the
"parallel binding" semantics of `let' that lets you do that.

While some details of language semantics can make analysis of code
easier for that (e.g. the non-aliasing constraints on arguments in
Fortran), I've never heard of anyone being able to use the
parallel-binding of "let" for that.

So, I stand by my claim: it's an Urban Legend.


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