From: "Drew Adams" <drew.adams@oracle.com>
To: "'Pascal J. Bourguignon'" <pjb@informatimago.com>,
<help-gnu-emacs@gnu.org>
Subject: RE: 'length' function for lists and cons cells?
Date: Sat, 23 Mar 2013 08:35:24 -0700 [thread overview]
Message-ID: <4E46BDE2694C476C9124DFFA7987CC48@us.oracle.com> (raw)
In-Reply-To: <877gkypauh.fsf@kuiper.lan.informatimago.com>
> > So if both, true lists and cons cells, are processed in a...
>
> proper-lists, not true lists.
> They all are true lists, ie. cons cells or nil.
Maybe for some people. For others, "true list" and "proper list" mean the same
thing. FWIW, Emacs itself calls such a beast a "true list".
From (elisp) `Cons Cells':
Also by convention, the CDR of the last cons cell in a
list is `nil'. We call such a `nil'-terminated structure
a "true list". In Emacs Lisp, the symbol `nil' is both
a symbol and a list with no elements. For convenience,
the symbol `nil' is considered to have `nil' as its CDR
(and also as its CAR).
Hence, the CDR of a true list is always a true list.
The CDR of a nonempty true list is a true list containing
all the elements except the first.
If the CDR of a list's last cons cell is some value
other than `nil', we call the structure a "dotted list"...
In any case, it is the description/meaning that is most important, not the name,
and there we agree.
next prev parent reply other threads:[~2013-03-23 15:35 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.22586.1363890109.855.help-gnu-emacs@gnu.org>
2013-03-21 20:49 ` 'length' function for lists and cons cells? Pascal J. Bourguignon
2013-03-22 2:38 ` Thorsten Jolitz
2013-03-22 7:27 ` Mark Skilbeck
2013-03-22 9:57 ` Thorsten Jolitz
[not found] ` <mailman.22632.1363946271.855.help-gnu-emacs@gnu.org>
2013-03-23 12:19 ` Pascal J. Bourguignon
2013-03-23 15:35 ` Drew Adams [this message]
[not found] ` <mailman.22706.1364052941.855.help-gnu-emacs@gnu.org>
2013-03-23 15:52 ` Pascal J. Bourguignon
2013-03-24 5:20 ` Drew Adams
[not found] ` <mailman.22618.1363919920.855.help-gnu-emacs@gnu.org>
2013-03-22 7:45 ` Barry Margolin
2013-03-23 11:31 ` Pascal J. Bourguignon
2013-03-21 18:21 Thorsten Jolitz
2013-03-21 20:02 ` Stephen Berman
2013-03-21 21:58 ` Thorsten Jolitz
2013-03-21 22:05 ` Drew Adams
[not found] ` <mailman.22591.1363903134.855.help-gnu-emacs@gnu.org>
2013-03-23 11:24 ` Pascal J. Bourguignon
2013-03-21 20:10 ` Drew Adams
2013-03-21 22:09 ` Thorsten Jolitz
[not found] ` <mailman.22588.1363896620.855.help-gnu-emacs@gnu.org>
2013-03-25 15:24 ` duthen.cnv
2013-03-25 20:02 ` Pascal J. Bourguignon
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