From: Barry Margolin <barmar@alum.mit.edu>
To: help-gnu-emacs@gnu.org
Subject: Re: Basic questions about elisp
Date: Fri, 06 Nov 2009 00:06:16 -0500 [thread overview]
Message-ID: <barmar-7BF563.00061606112009@news.eternal-september.org> (raw)
In-Reply-To: 87iqdpdog1.fsf@galatea.local
In article <87iqdpdog1.fsf@galatea.local>,
pjb@informatimago.com (Pascal J. Bourguignon) wrote:
> Francis Moreau <francis.moro@gmail.com> writes:
>
> > Hello,
> >
> > I'm trying to learn elisp and have a couple of basic questions.
> >
> > I'm iterating over a list using dotimes, but in the body of dotimes,
> dolist dolist
>
> > the list can mutate. For example I have:
> >
> > (dolist (elt lst)
> > ;; some codes
> > (nconc lst '(2)))
>
> This is an infinite loop. It will break when the program runs out of
> memory.
It also modifies a literal, which modifies the function itself
(resulting in a circular list of (2 2 2 2 ...)). Change that nconc to:
(nconc lst (list 2))
to avoid that.
>
>
> > This adds/appends a new element to 'lst' list. It looks like 'dotimes'
> dolist
> > doesn't like it.
>
> If you are not careful, you won't be able to program...
>
>
> > I also need to iterate over elements of a vector. I basically use a
> > 'while' loop as above. Is there any helper to do that, I looked at
> > "(elisp) Sequences Arrays Vectors" but found nothing appropriate.
>
> (require 'cl)
> (loop for element in list do (something element))
> (loop for element across vector do (something element))
>
>
> > And finally, is it the good place to ask such questions about elisp ?
>
> Yes, it's right here.
--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***
prev parent reply other threads:[~2009-11-06 5:06 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-05 11:13 Basic questions about elisp Francis Moreau
2009-11-05 11:50 ` Lennart Borgman
[not found] ` <mailman.10118.1257421858.2239.help-gnu-emacs@gnu.org>
2009-11-05 12:07 ` Francis Moreau
2009-11-05 12:44 ` Lennart Borgman
2009-11-05 12:59 ` David Kastrup
2009-11-05 14:25 ` Francis Moreau
2009-11-05 14:37 ` Pascal J. Bourguignon
2009-11-05 14:58 ` Pascal J. Bourguignon
2009-11-05 12:57 ` tomas
[not found] ` <mailman.10122.1257425638.2239.help-gnu-emacs@gnu.org>
2009-11-05 14:29 ` Francis Moreau
2009-11-05 14:41 ` Pascal J. Bourguignon
2009-11-05 15:06 ` David Kastrup
2009-11-06 16:03 ` Francis Moreau
2009-11-06 16:49 ` David Kastrup
2009-11-06 20:53 ` Francis Moreau
2009-11-06 21:18 ` Pascal J. Bourguignon
2009-11-07 14:49 ` Francis Moreau
2009-11-07 17:50 ` Pascal J. Bourguignon
2009-11-08 9:46 ` tomas
[not found] ` <mailman.10266.1257674088.2239.help-gnu-emacs@gnu.org>
2009-11-09 20:51 ` Francis Moreau
2009-11-08 15:18 ` Francis Moreau
2009-11-08 16:58 ` tomas
2009-11-08 17:12 ` Pascal J. Bourguignon
2009-11-09 21:04 ` Francis Moreau
2009-11-10 12:11 ` Joost Kremers
2009-11-10 14:16 ` Francis Moreau
2009-11-10 18:53 ` David Kastrup
2009-11-06 5:06 ` Barry Margolin [this message]
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