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Re: `append' vs. `nconc'


From: Barry Margolin
Subject: Re: `append' vs. `nconc'
Date: Thu, 31 Dec 2015 21:53:17 -0500
User-agent: MT-NewsWatcher/3.5.3b3 (Intel Mac OS X)

In article <mailman.1440.1451588113.843.help-gnu-emacs@gnu.org>,
 Emanuel Berg <embe8573@student.uu.se> wrote:

> <tomas@tuxteam.de> writes:
> 
> > - it's very obvious It's a local value you are
> > keeping in your little scope. (One might argue that
> > then, it's an idiomatic way to emphasize this fact
> > to the (human) reader...)
> 
> The thing here is, when it is very obvious and
> everything is small and easy to handle, what is the
> actual gain in time and space not using `append'?
> 
> Answer:
> 
>     -> 0
> 
> But OK, as a matter of principle it can be a cool
> thing to know/do.

NCONC was created at least 40 years ago, when computers were slow and 
had very little memory (a modern cellphone is has the power of a roomful 
of 70's-era mainframes). And garbage collection was also very slow 
(generational GC hadn't been developed yet).

So optimizations like NCONC could be very useful back then. These days, 
the benefit is probably very little.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***


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