From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-0.3 required=5.0 tests=BAYES_00,
	REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: 103376,9901a52b5f698b34
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news3.google.com!border1.nntp.dca.giganews.com!border2.nntp.dca.giganews.com!nntp.giganews.com!newsfeed00.sul.t-online.de!t-online.de!npeer.de.kpn-eurorings.net!newsfeed.arcor.de!news.arcor.de!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: String Problem
Newsgroups: comp.lang.ada
User-Agent: 40tude_Dialog/2.0.14.1
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Reply-To: mailbox@dmitry-kazakov.de
Organization: cbb software GmbH
References: <JFnTe.50568$HM1.1436055@twister1.libero.it>
 <sa4u0gwpms7.fsf@snoopy.microcomaustralia.com.au>
 <IfMTe.2473$9x2.1703@newsread3.news.pas.earthlink.net>
Date: Thu, 8 Sep 2005 09:23:25 +0200
Message-ID: <7r7vpvcetypn.1dbi0rpoxkyku$.dlg@40tude.net>
NNTP-Posting-Date: 08 Sep 2005 09:23:14 MEST
NNTP-Posting-Host: 647a6f67.newsread2.arcor-online.net
X-Trace: 
 DXC=\HUSIJU6QcU\6[GEd:nl>[Q5U85hF6f;TjW\KbG]kaMXQ>n?D9BSA]\fn`O1iBMRj^WRXZ37ga[7Zn919Q4_`VjYB8=X\UUgbkT
X-Complaints-To: abuse@arcor.de
Xref: g2news1.google.com comp.lang.ada:4517
Date: 2005-09-08T09:23:14+02:00
List-Id: <comp.lang.ada>

On Thu, 08 Sep 2005 01:14:16 GMT, Jeffrey R. Carter wrote:

> Similar uses of the phrase "null string" may be found in the descriptions of the 
> various Ada.Strings.* packages, and in other places. It does not seem to ever be 
> described. The meaning seems to be a value of type String with 'Length = 0, or 
> a[n] [Un]Bounded_String such that the function Length returns 0. It could also 
> be defined as a string that is equal to "".

It could also be: "null string" is an identity element (zero) for the
concatenation (&): for any A : String "" & A = A and A & "" = A. It makes
sense if we consider strings as atomic values. "Empty string" corresponds
the view on strings as containers/sets.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de