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=ham
	autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,fa18fb47ddd229a7
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2003-12-10 08:47:01 PST
Path: 
 archiver1.google.com!news2.google.com!newsfeed2.dallas1.level3.net!news.level3.com!news-out.visi.com!petbe.visi.com!news.tele.dk!news.tele.dk!small.news.tele.dk!news-FFM2.ecrc.net!informatik.uni-bremen.de!cs.tu-berlin.de!uni-duisburg.de!not-for-mail
From: Georg Bauhaus <sb463ba@l1-hrz.uni-duisburg.de>
Newsgroups: comp.lang.ada
Subject: Re: Proposed change to BC iterator parameters [limitedness]
Date: Wed, 10 Dec 2003 16:47:00 +0000 (UTC)
Organization: GMUGHDU
Message-ID: <br7im4$7rd$1@a1-hrz.uni-duisburg.de>
References: <mailman.69.1071063420.31149.comp.lang.ada@ada-france.org>
NNTP-Posting-Host: l1-hrz.uni-duisburg.de
X-Trace: a1-hrz.uni-duisburg.de 1071074820 8045 134.91.1.34 (10 Dec 2003
 16:47:00 GMT)
X-Complaints-To: usenet@news.uni-duisburg.de
NNTP-Posting-Date: Wed, 10 Dec 2003 16:47:00 +0000 (UTC)
User-Agent: tin/1.5.8-20010221 ("Blue Water") (UNIX) (HP-UX/B.11.00
 (9000/800))
Xref: archiver1.google.com comp.lang.ada:3316
Date: 2003-12-10T16:47:00+00:00
List-Id: <comp.lang.ada>

amado.alves <amado.alves@netcabo.pt> wrote:
: 
:
: I do like indefinite formals, but I pass well
: without limited ones. Most limited formals I've seen in libraries
: are accompanied by a formal assignment operation or some such,
: which prety much defeats the purpose of their (formal) limitedness,
: i.e. their logic is in clash with their definition. 

Sometimes I dearly wanted limited records but was defeated
by the library that could not store them (storing them was the
intention):

  type T(x: access D) is tagged limited private;

I want x to be constant plus initialised once and for all,
so access discriminants are just fine, but T has to
be limited then. Which would have been o.K., but not every library
allows this.

What should I do? Use pointers to the records? Afaics, this leads to
allocators or library level declarations (not always possible when
an unkown number of objects' lives start during the program's run?)
or 'unchecked_access.

Or use record compontens of
  type D_Ptr is access constant D;
and get rid of the access discriminants, and have a definite type?
How do I prevent then that tagged records can be declared but not
initialised?

Any suggestion would be very welcome.


Thanks,
-- Georg