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Re: Always using let*


From: Pascal J. Bourguignon
Subject: Re: Always using let*
Date: Mon, 15 Sep 2014 04:12:56 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux)

Emanuel Berg <address@hidden> writes:

> Drew Adams <address@hidden> writes:
>
>> Lisps such as Common Lisp were specifically designed
>> with this parallel evaluation in mind. The spec (and
>> CLTL(2))
>
> CLTL(2) = "Common Lisp The Language", 2nd edition, by
> Guy Steele.
>
> Here it is, as a PDF - 1097 pages, according to
> 'exiftool':
>
> http://www.lispmachine.net/books/common_lisp_the_language.pdf
>
>> Whether a given Common Lisp implementation takes
>> advantage of this inherent parallelism is optional.
>> Likewise for the other explicitly parallel constructs
>> in CL.
>>
>> For `psetf', for example, CLTL says that "the
>> assignments of new values are done in parallel. ..."
>
> Again, what do you mean by "parallel"? Is it parallel
> (i.e., truly concurrent) computation on different CPUs
> (cores), or is it some other kind of parallelism or
> pipelining?

It means that:

     (psetf a b 
            b a)

exchanges the values of b and a.

-- 
__Pascal Bourguignon__                 http://www.informatimago.com/
“The factory of the future will have only two employees, a man and a
dog. The man will be there to feed the dog. The dog will be there to
keep the man from touching the equipment.” -- Carl Bass CEO Autodesk


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