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: a07f3367d7,d00514eb0749375b
X-Google-Attributes: gida07f3367d7,public,usenet
X-Google-NewGroupId: yes
X-Google-Language: ENGLISH,ASCII
Path: 
 g2news1.google.com!postnews.google.com!l20g2000yqm.googlegroups.com!not-for-mail
From: Phil Clayton <phil.clayton@lineone.net>
Newsgroups: comp.lang.ada
Subject: Re: initialize an array (1-D) at elaboration using an expression
 based on the index?
Date: Sun, 24 Oct 2010 15:48:21 -0700 (PDT)
Organization: http://groups.google.com
Message-ID: 
 <ade14be1-de0a-4dfa-a2a5-6009fa6da139@l20g2000yqm.googlegroups.com>
References: <i9amkr$goj$1@speranza.aioe.org>
 <1f6bad81-e3d2-428b-a1a0-45acc7f96f68@m7g2000yqm.googlegroups.com>
 <9df4e5eb-fba7-4e8c-ba44-cd1ad4081d3b@26g2000yqv.googlegroups.com>
NNTP-Posting-Host: 91.110.141.84
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
X-Trace: posting.google.com 1287960501 11138 127.0.0.1 (24 Oct 2010 22:48:21
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Sun, 24 Oct 2010 22:48:21 +0000 (UTC)
Complaints-To: groups-abuse@google.com
Injection-Info: l20g2000yqm.googlegroups.com; posting-host=91.110.141.84;
 posting-account=v7gx3AoAAABfjb9m5b7l_Lt2KVEgQBIe
User-Agent: G2/1.0
X-HTTP-UserAgent: Mozilla/5.0 (X11; U; Linux i686; en-GB; rv:1.9.0.15)
 Gecko/2009102704 Fedora/3.0.15-1.fc10 Firefox/3.0.15,gzip(gfe)
Xref: g2news1.google.com comp.lang.ada:14726
Date: 2010-10-24T15:48:21-07:00
List-Id: <comp.lang.ada>

On Oct 24, 5:40=A0pm, Shark8 <onewingedsh...@gmail.com> wrote:
> Interesting.
> It doesn't look like it would be very extensible into multidimensional
> arrays though.
>
> Perhaps something like an 'Initialize attribute [on the type, not the
> variables thereof] which would take an Access to Function returning
> that type. It would have to be called only in the case of K :
> Array_Type because K : Array_Type:=3D (Others =3D> <>) is providing an
> initialization of the default value to all the elements [which is
> unlikely to match the initialization's value].
>
> However, it is the internals of the function which are interesting if
> this route were taken. =A0The indexings need to be discrete types,
> however they need not be numeric or even all the same type. This
> results in the following being valid:
> =A0 Type A_HighSchool_Letterjacket_Type is Array (Size, Color,
> Character) of Byte; -- A jacket-maker's inventory for letter-jackets.
>
> So we can't have an "array" representing the indicies for use in the
> initialization-function.
> (ex: ---Invalid
> =A0 For Index_1 in Index(1)'Range loop
> =A0 =A0 For Index_2 in Index(2)'Range loop
> =A0 =A0 =A0 For Index_3 in Index(3)'Range loop
> =A0 =A0 =A0 =A0 -- do stuff for calculating the value stored;
> =A0 =A0 =A0 end loop;
> =A0 =A0 end loop;
> =A0 end loop;
> )

Good point.  I think it is ok for multidimensional arrays given the
right interpretation of a "for expression" though.

In fact, it should probably be called a "for aggregate".  It looked
like Adam was suggesting that it would just be another case of
array_aggregate (4.3.3) in the syntax.  So a nested "for aggregate"
would, presumably, work as a subaggregate allowing multidimensional
arrays to handled.

Another way to think about this is that

  (for I in T =3D> F(I))

would be equivalent to and interchangeable with the named aggregate

  (X1 =3D> F(X1), X2 =3D> F(X2), ...)

where X1, X2, ... are the elements of subtype T.  With that view, it
seems a fairly simple extension to the language from a technical
perspective.

Phil