From: Tim X <timx@nospam.dev.null>
To: help-gnu-emacs@gnu.org
Subject: Re: Basic Emacs Lisp question
Date: Wed, 30 Apr 2008 18:31:23 +1000 [thread overview]
Message-ID: <877iefeobo.fsf@lion.rapttech.com.au> (raw)
In-Reply-To: 87zlrctlbl.fsf@blackbart.sedgenet
tyler <tyler.smith@mail.mcgill.ca> writes:
> Matthias Pfeifer <pfemat@web.de> writes:
>
>> What is the difference between
>>
>> (list 0 nil -1)
>>
>> and
>>
>> '(0 nil -1)
>>
>
> In this instance, nothing. However, the '(...) form leaves it's
> arguments unevaluated (quoted), while (list ...) evaluates them. Since
> 0, nil and -1 all evaluate to themselves there is no difference in this
> case. However, the following two statements are different:
>
> (list 0 fill-column -1)
>
> '(0 fill-column -1)
>
> A good place to start learning is the Introduction to Programming in
> Emacs Lisp, which is available from gnu.org, if it isn't already present
> in your info directory (i.e., C-h i m emacs lisp intro <ret>).
>
Are you sure there is no difference? In many lisp dialects, the second
form is more like a constant and cannot be modified in a reliable
manner - IIRC this is due to how memory is allocated for the
quoted form. In the first one, memory is allocated dynamically and so
can be safely modified.
Tim
--
tcross (at) rapttech dot com dot au
next prev parent reply other threads:[~2008-04-30 8:31 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-29 15:49 Basic Emacs Lisp question Matthias Pfeifer
2008-04-29 17:56 ` Giorgos Keramidas
2008-04-30 1:21 ` Giorgos Keramidas
2008-04-30 8:37 ` Tim X
2008-04-30 15:26 ` David Kastrup
2008-04-30 18:36 ` Giorgos Keramidas
2008-05-01 9:25 ` Johan Bockgård
2008-04-29 21:14 ` tyler
2008-04-30 8:31 ` Tim X [this message]
2008-05-05 13:38 ` tyler
-- strict thread matches above, loose matches on Subject: below --
2014-09-09 19:35 Basic emacs lisp question Ken
2014-09-09 19:52 ` Thorsten Jolitz
2014-09-09 21:05 ` Thorsten Jolitz
[not found] ` <mailman.8562.1410296811.1147.help-gnu-emacs@gnu.org>
2014-09-09 23:02 ` Emanuel Berg
[not found] ` <mailman.8561.1410292382.1147.help-gnu-emacs@gnu.org>
2014-09-09 20:07 ` Emanuel Berg
[not found] ` <874mwgv93m.fsf@gmail.com>
2014-09-09 20:44 ` Emanuel Berg
[not found] ` <87y4tsts4t.fsf@gmail.com>
2014-09-09 22:31 ` Emanuel Berg
2014-09-10 0:49 ` Robert Thorpe
2014-09-10 1:21 ` Ken
2014-09-10 6:00 ` Glyn Millington
2014-09-10 14:31 ` Ken
2014-09-10 13:12 ` Phillip Lord
2014-09-10 14:06 ` Thien-Thi Nguyen
2014-09-10 14:26 ` Stefan Monnier
2014-09-10 15:45 ` Phillip Lord
2014-09-10 16:59 ` Stefan Monnier
2014-09-11 11:10 ` Phillip Lord
2014-09-11 11:10 ` Phillip Lord
[not found] ` <mailman.8619.1410357764.1147.help-gnu-emacs@gnu.org>
2014-09-10 21:39 ` Emanuel Berg
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