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=-0.9 required=5.0 tests=BAYES_00,FORGED_GMAIL_RCVD,
	FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4
Path: 
 eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!usenet.blueworldhosting.com!feeder01.blueworldhosting.com!peer02.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!post02.iad.highwinds-media.com!fx19.iad.POSTED!not-for-mail
From: Shark8 <OneWingedShark@gmail.com>
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64;
 rv:32.0) Gecko/20100101 Thunderbird/32.0a1
MIME-Version: 1.0
Newsgroups: comp.lang.ada
Subject: Comments requested for a couple of Ada-Comments submissions
References: <lpn9ic$acs$1@dont-email.me> <58Kvv.9105$Zt3.1101@fx02.iad>
 <aecf81df-dc39-4bbf-9990-c8367587daba@googlegroups.com>
 <c2al2lFj394U1@mid.individual.net>
 <f8bc1877-bc06-43a9-bc92-82783dec7741@googlegroups.com>
 <lyfvi73hdu.fsf@pushface.org> <61zr552fwaif$.1gzem1sdpvtac.dlg@40tude.net>
 <lppklk$rek$1@loke.gir.dk>
In-Reply-To: <lppklk$rek$1@loke.gir.dk>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
Message-ID: <XWYvv.380837$OF6.324701@fx19.iad>
X-Complaints-To: abuse@teranews.com
NNTP-Posting-Date: Fri, 11 Jul 2014 21:46:31 UTC
Organization: TeraNews.com
Date: Fri, 11 Jul 2014 15:46:33 -0600
X-Received-Bytes: 2404
X-Received-Body-CRC: 2773434281
Xref: news.eternal-september.org comp.lang.ada:20886
Date: 2014-07-11T15:46:33-06:00
List-Id: <comp.lang.ada>

On 11-Jul-14 15:24, Randy Brukardt wrote:
> This is roughly what GNAT is doing, and I think this is horrible. An
> attribute is some sort of function, and it would never be possible to write
> a function that works like this. I don't want more magic in the language if
> we can help it. Moreover, this ought to have the semantics of an aggregate
> (vis-a-vis temporaries, build-in-place, and the like), and as such it ought
> to look like an aggregate.

I agree -- I think this should not be an attribute, nor the addition of 
new keywords.

Perhaps something along the lines of Extension Aggregates [ref 4.3.2].
-- Reminder --

extension_aggregate ::=
     (ancestor_part with record_component_association_list)

ancestor_part ::= expression | subtype_mark

-- New Syntax --
partial_aggregate ::=
     (modified_part with all others => <>)

where modified_part denotes the portion being updated, in list/alternate 
form...
-- Given record a containing integer fields B, C, D:
A:= (B => 1, D => 2 with all others => <>);
-- Given bit-array A with indices 1..16:
A:= (1..4 => 1, 9..16 => 0 with all others => <>);

It obviously wouldn't work on a unconstrained array-type initialization, 
where the variable would try to get its constraints from the right-hand 
side, but considering the intended use I don't see why that would be a 
bad thing.
Just an idea.