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=-1.9 required=5.0 tests=BAYES_00
	autolearn=unavailable autolearn_force=no version=3.4.4
Path: 
 eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!feeder.eternal-september.org!gandalf.srv.welterde.de!news.jacob-sparre.dk!franka.jacob-sparre.dk!pnx.dk!.POSTED.rrsoftware.com!not-for-mail
From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: How to get Ada to ?cross the chasm??
Date: Fri, 4 May 2018 17:02:21 -0500
Organization: JSA Research & Innovation
Message-ID: <pcil9d$ejg$1@franka.jacob-sparre.dk>
References: 
 <1c73f159-eae4-4ae7-a348-03964b007197@googlegroups.com><slrnpdpiv9.ntv.address@is.invalid><pbr3mi$leu$1@franka.jacob-sparre.dk>
 <87k1su7nag.fsf@nightsong.com><pbtlno$3k2$1@franka.jacob-sparre.dk>
 <87po2la2qt.fsf@nightsong.com><87in8buttb.fsf@jacob-sparre.dk>
 <87wowqpowu.fsf@nightsong.com><16406268-83df-4564-8855-9bd0fe9caac0@googlegroups.com><87o9i2pkcr.fsf@nightsong.com>
 <pc8l7e$km5$1@franka.jacob-sparre.dk><87in88m43h.fsf@nightsong.com><cd866ee8-ad4d-489e-a38b-d8e5f5d4af00@googlegroups.com><87efiuope8.fsf@nightsong.com><322f9b26-01de-4753-bb50-6ef2f3d993d8@googlegroups.com><87a7th9pd1.fsf@nightsong.com><bbda04b9-0f91-47c5-9193-279b667f503c@googlegroups.com><87h8no1nli.fsf@nightsong.com>
 <pcg2cc$h52$1@franka.jacob-sparre.dk><874ljo1hvy.fsf@nightsong.com>
 <pcg6u7$hjr$1@franka.jacob-sparre.dk> <lybmdv28p5.fsf@pushface.org>
Injection-Date: Fri, 4 May 2018 22:02:21 -0000 (UTC)
Injection-Info: franka.jacob-sparre.dk;
 posting-host="rrsoftware.com:24.196.82.226";
	logging-data="14960"; mail-complaints-to="news@jacob-sparre.dk"
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2900.5931
X-RFC2646: Format=Flowed; Original
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.7246
Xref: reader02.eternal-september.org comp.lang.ada:51991
Date: 2018-05-04T17:02:21-05:00
List-Id: <comp.lang.ada>

"Simon Wright" <simon@pushface.org> wrote in message 
news:lybmdv28p5.fsf@pushface.org...
> "Randy Brukardt" <randy@rrsoftware.com> writes:
>
>> All of the Ada containers have "cursors", which serve the reference
>> function.
>
> Tree cursors are defined to continue to designate an element even if it
> gets moved in the tree (bcause of insertion/deletion of other
> elements). Is this true of all cursors? (I may have got muddled by the
> "tampering" issue).

Yes. There's an issue with vector cursors, they can become invalid because 
of "sliding" -- but vector cursors are rarely used (since the entire point 
of the container is to allow indexing, it's usually accessed that way).

Tampering (in part) is a way to ensure that remains true; you aren't allowed 
to insert into a container while it is being iterated, for instance.

                       Randy.