From: Michael Heerdegen <michael_heerdegen@web.de>
To: Constantino Calancha <f92capac@gmail.com>
Cc: "21782@debbugs.gnu.org" <21782@debbugs.gnu.org>
Subject: bug#21782: 25.0.50; New functions nfront/front
Date: Fri, 30 Oct 2015 15:09:10 +0100 [thread overview]
Message-ID: <87a8r0sb21.fsf@web.de> (raw)
In-Reply-To: <op.x7aszghd32915k@calancha-ilc.kek.jp> (Constantino Calancha's message of "Fri, 30 Oct 2015 11:53:30 +0900")
"Constantino Calancha" <f92capac@gmail.com> writes:
> Im sorry Michael, but i dont see your point: do you mean the fact to
> call nreverse twice? nreverse is in fact very efficient; and last
> already use nthcdr in its implementation.
`nreverse` efficiently does what is supposed to do, yes. But it is
O(l), where l is the length of the list arg.
In addition, the newly created `nreverse'd list must be garbage
collected.
The `copy-sequence' call in `front' is bad for the same reason.
OTOH nfront can be implemented in O(n), where n is the number argument
to nfront.
Michael.
next prev parent reply other threads:[~2015-10-30 14:09 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-29 9:57 bug#21782: 25.0.50; New functions nfront/front Tino Calancha
2015-10-29 15:25 ` Artur Malabarba
2015-10-30 1:25 ` Tino Calancha
2015-10-30 2:38 ` Michael Heerdegen
2015-10-30 2:53 ` Constantino Calancha
2015-10-30 9:45 ` Artur Malabarba
2015-10-30 10:10 ` Tino Calancha
2015-10-30 10:03 ` Nicolas Petton
2015-10-30 10:11 ` Tino Calancha
2015-10-30 14:09 ` Michael Heerdegen [this message]
2015-10-30 18:06 ` Tino Calancha
2015-10-30 2:10 ` Tino Calancha
2015-10-30 1:33 ` Richard Stallman
2015-10-30 1:41 ` Constantino Calancha
[not found] ` <mailman.1293.1446168906.7904.bug-gnu-emacs@gnu.org>
2015-10-31 22:44 ` Alan Mackenzie
2017-05-18 4:08 ` Tino Calancha
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