From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
	ip-172-31-65-14.ec2.internal
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=3.0 tests=BAYES_00,T_SCC_BODY_TEXT_LINE
	autolearn=ham autolearn_force=no version=3.4.6
Path: eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: strange cursor in nested containers
Date: Thu, 20 Apr 2023 15:59:35 +0100
Organization: A noiseless patient Spider
Message-ID: <lyttxak3ag.fsf@pushface.org>
References: <a346f13d-9876-488a-9472-4563de130311n@googlegroups.com>
	<6aa39f27-62ca-4486-9fc7-1c713da5b098n@googlegroups.com>
MIME-Version: 1.0
Content-Type: text/plain
Injection-Info: dont-email.me; posting-host="9fefc01f5d17daffe51cd7c6729b1277";
	logging-data="688487"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX181aGWKO0DQ7708hf0C7FIJXrqdXxarwZA="
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.1 (darwin)
Cancel-Lock: sha1:gL2qlm4mocVEC/nm7RzQM8L3WLM=
	sha1:QJPbpeAiZUmUOYhNmZ+397eucmo=
Xref: news.eternal-september.org comp.lang.ada:65120
List-Id: <comp.lang.ada>

Egil H H <ehh.public@gmail.com> writes:

> Each call to `element(n)` returns a _copy_ of the element, which in
> this case includes the enitre doubly linked list

This is indeed the problem, thanks!

I hadn't considered the effect of renaming a function call; the cursor
constructed inside query_net refers to the locally renamed copy of
type_net, which will be destroyed on exit from query_net.

>                                                  (and since `net` is a
> renames of `element(n), you would have gotten multiple copies if you
> had called `net` multiple times inside query net)

This appears to say that this renaming of a function call results in
something like a macro, but I think that

   R : T renames Func;

is more like

   R : constant T := Func;
   
ARM 8.5(3) says

   "The elaboration of a renaming_declaration evaluates the name that
   follows the reserved word renames and thereby determines the view and
   entity denoted by this name (the renamed view and renamed entity). A
   name that denotes the renaming_declaration denotes (a new view of)
   the renamed entity."