From: "Pascal J. Bourguignon" <pjb@informatimago.com>
To: help-gnu-emacs@gnu.org
Subject: Re: Is this use of nreverse a good practice?
Date: Sun, 01 Feb 2015 14:02:02 +0100 [thread overview]
Message-ID: <87k301rdit.fsf@kuiper.lan.informatimago.com> (raw)
In-Reply-To: mailman.19096.1422792521.1147.help-gnu-emacs@gnu.org
Marcin Borkowski <mbork@wmi.amu.edu.pl> writes:
> Hi there,
>
> I'm writing a small function which should build a list and return it.
> What I'm doing is more or less this:
>
> (defun myfunc ()
> (let ((list-var))
> (while CONDITION
> (DO-SOMETHING)
> (push SOME-ELEMENT list-var))
> (nreverse list-var)))
>
> A more concrete example:
>
> (defun reverse-range (n)
> (let ((list-var))
> (while (> n 0)
> (push n list-var)
> (decf n))
> (nreverse list-var)))
>
> (reverse-range 5)
>
> ⇒ (5 4 3 2 1)
>
> Is this usage of `nreverse' correct? I guess it is, since list-var is
> only a temporary variable and destructing it doesn't bother me.
> However, I'm never sure I'm doing things right when using
> nconc/nreverse, so I though I'd better ask...
Yes, this is THE use case for nreverse.
--
__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
next parent reply other threads:[~2015-02-01 13:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.19096.1422792521.1147.help-gnu-emacs@gnu.org>
2015-02-01 13:02 ` Pascal J. Bourguignon [this message]
2015-02-01 12:08 Is this use of nreverse a good practice? Marcin Borkowski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87k301rdit.fsf@kuiper.lan.informatimago.com \
--to=pjb@informatimago.com \
--cc=help-gnu-emacs@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.