From mboxrd@z Thu Jan  1 00:00:00 1970
Path: news.gmane.org!not-for-mail
From: Alan Mackenzie <acm@muc.de>
Newsgroups: gmane.emacs.help
Subject: Re: to big nest level of recursion
Date: Sat, 25 Mar 2006 10:30:32 +0000
Organization: muc.de e.V. -- private internet access
Message-ID: <94630e.09.ln@acm.acm>
References: <mailman.21.1142976703.14011.help-gnu-emacs@gnu.org>
NNTP-Posting-Host: main.gmane.org
X-Trace: sea.gmane.org 1143290457 24813 80.91.229.2 (25 Mar 2006 12:40:57 GMT)
X-Complaints-To: usenet@sea.gmane.org
NNTP-Posting-Date: Sat, 25 Mar 2006 12:40:57 +0000 (UTC)
Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sat Mar 25 13:40:56 2006
Return-path: <help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org>
Envelope-to: geh-help-gnu-emacs@m.gmane.org
Original-Received: from lists.gnu.org ([199.232.76.165])
	by ciao.gmane.org with esmtp (Exim 4.43)
	id 1FN84a-0008Ap-HD
	for geh-help-gnu-emacs@m.gmane.org; Sat, 25 Mar 2006 13:40:52 +0100
Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43)
	id 1FN84a-0005a1-30
	for geh-help-gnu-emacs@m.gmane.org; Sat, 25 Mar 2006 07:40:52 -0500
Original-Path: shelby.stanford.edu!newsfeed.stanford.edu!news.tele.dk!news.tele.dk!small.news.tele.dk!newsfeed00.sul.t-online.de!newsfeed01.sul.t-online.de!t-online.de!news.belwue.de!news-peer.in.tum.de!news.muc.de!not-for-mail
Original-Newsgroups: gnu.emacs.help
Original-Lines: 18
Original-NNTP-Posting-Host: acm.muc.de
Original-X-Trace: marvin.muc.de 1143286260 64548 193.149.49.134 (25 Mar 2006 11:31:00
	GMT)
Original-X-Complaints-To: news-admin@muc.de
Original-NNTP-Posting-Date: 25 Mar 2006 11:31:00 GMT
User-Agent: tin/1.4.5-20010409 ("One More Nightmare") (UNIX) (Linux/2.0.35
	(i686))
Original-Xref: shelby.stanford.edu gnu.emacs.help:138371
Original-To: help-gnu-emacs@gnu.org
X-BeenThere: help-gnu-emacs@gnu.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Users list for the GNU Emacs text editor <help-gnu-emacs.gnu.org>
List-Unsubscribe: <http://lists.gnu.org/mailman/listinfo/help-gnu-emacs>,
	<mailto:help-gnu-emacs-request@gnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/help-gnu-emacs>
List-Post: <mailto:help-gnu-emacs@gnu.org>
List-Help: <mailto:help-gnu-emacs-request@gnu.org?subject=help>
List-Subscribe: <http://lists.gnu.org/mailman/listinfo/help-gnu-emacs>,
	<mailto:help-gnu-emacs-request@gnu.org?subject=subscribe>
Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org
Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org
Xref: news.gmane.org gmane.emacs.help:33979
Archived-At: <http://permalink.gmane.org/gmane.emacs.help/33979>

David Reitter <david.reitter@gmail.com> wrote on Tue, 21 Mar 2006
21:31:29 +0000:

[ .... ]

> Maybe it's a consolation for you that for every recursive algorithm,
> you can formulate an iterative version. And you don't bloat a call
> stack when you do so.

This is not true.  There are algorithms that are intrinsically recursive
and cannot be formulated with mere iteration (such as the Ackermann
function, specially invented to demonstrate this).

-- 
Alan Mackenzie (Munich, Germany)
Email: aacm@muuc.dee; to decode, wherever there is a repeated letter
(like "aa"), remove half of them (leaving, say, "a").