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bug#21782: 25.0.50; New functions nfront/front
From: |
Michael Heerdegen |
Subject: |
bug#21782: 25.0.50; New functions nfront/front |
Date: |
Fri, 30 Oct 2015 15:09:10 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) |
"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.
bug#21782: 25.0.50; New functions nfront/front, Tino Calancha, 2015/10/29
bug#21782: 25.0.50; New functions nfront/front, Richard Stallman, 2015/10/29
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