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-Thread: 103376,2153d570c2f03e29
X-Google-NewGroupId: yes
X-Google-Attributes: gida07f3367d7,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
X-Received: by 10.66.72.199 with SMTP id f7mr48396pav.12.1355789228207;
        Mon, 17 Dec 2012 16:07:08 -0800 (PST)
MIME-Version: 1.0
Path: 
 s9ni50706pbb.0!nntp.google.com!news.glorb.com!feeder.erje.net!us.feeder.erje.net!newsfeed.straub-nv.de!reality.xs3.de!news.jacob-sparre.dk!munin.jacob-sparre.dk!pnx.dk!.POSTED!not-for-mail
From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Question about library-level functions
Date: Mon, 17 Dec 2012 18:07:05 -0600
Organization: Jacob Sparre Andersen Research & Innovation
Message-ID: <kaoc3b$ud6$1@munin.nbi.dk>
References: <f7a79646-eb34-42c6-b1df-ccbb8c59437f@googlegroups.com>
 <ly7goiz60i.fsf@pushface.org>
 <a7a82a85-48e4-4ded-b090-06f62bd3b0b6@googlegroups.com>
NNTP-Posting-Host: static-69-95-181-76.mad.choiceone.net
X-Trace: munin.nbi.dk 1355789227 31142 69.95.181.76 (18 Dec 2012 00:07:07 GMT)
X-Complaints-To: news@jacob-sparre.dk
NNTP-Posting-Date: Tue, 18 Dec 2012 00:07:07 +0000 (UTC)
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2900.5931
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157
X-RFC2646: Format=Flowed; Original
Date: 2012-12-17T18:07:05-06:00
List-Id: <comp.lang.ada>

"AdaMagica" <christ-usch.grein@t-online.de> wrote in message 
news:a7a82a85-48e4-4ded-b090-06f62bd3b0b6@googlegroups.com...
...
>Creating via anonymous access is evil - how can ou ever deallocate it? This 
>should be verboten by the language.

A few too many words here: "anonymous access is evil" would have been 
enough. (At least for access-to-object.) The rules for accessibility (and 
thus finalization) are impossible to understand and typically require 
dynamic checks. Dynamic accessibility checks are surely evil, as they add 
overhead, create a "tripping hazard" (some uses are OK, others fail at 
runtime, which is not indicated by the specification), and only detect a 
minority of problems (most real uses have to resort to 'Unchecked_Access 
anyway).

These types were a mistake in Ada 95 and expanding their use compounded the 
mistake. Too bad it wasn't obvious from the beginning.

Vis-a-vis your original comment -- Ada 2012 at least gives restrictions that 
let users self-impose what the language does not:
   pragma Restrictions (No_Anonymous_Allocators); -- H.4(8.1/3)
   pragma Restrictions (No_Coextensions); -- H.4(8.2/3)
   pragma Restrictions (No_Access_Parameter_Allocators); -- H.4(8.3/3)

Can't make these the default for compatibility reasons, of course.

                                            Randy.