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: 103376,2bbd7f65ab12f156
X-Google-Attributes: gid103376,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!postnews.google.com!x35g2000prf.googlegroups.com!not-for-mail
From: Adam Beneschan <adam@irvine.com>
Newsgroups: comp.lang.ada
Subject: Re: Q: how to copy contents and use ancestor's constraints at the
 same time ?
Date: Mon, 13 Aug 2007 14:33:42 -0700
Organization: http://groups.google.com
Message-ID: <1187040822.123740.52460@x35g2000prf.googlegroups.com>
References: <46c0c9e8$1_3@news.bluewin.ch>
NNTP-Posting-Host: 66.126.103.122
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
X-Trace: posting.google.com 1187040823 20094 127.0.0.1 (13 Aug 2007 21:33:43
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Mon, 13 Aug 2007 21:33:43 +0000 (UTC)
In-Reply-To: <46c0c9e8$1_3@news.bluewin.ch>
User-Agent: G2/1.0
X-HTTP-UserAgent: Mozilla/5.0 (X11; U; Linux x86_64; en-US;
 rv:1.7.12) Gecko/20050922 Fedora/1.7.12-1.3.1,gzip(gfe),gzip(gfe)
Complaints-To: groups-abuse@google.com
Injection-Info: x35g2000prf.googlegroups.com; posting-host=66.126.103.122;
   posting-account=ps2QrAMAAAA6_jCuRt2JEIpn5Otqf_w0
Xref: g2news2.google.com comp.lang.ada:1430
Date: 2007-08-13T14:33:42-07:00
List-Id: <comp.lang.ada>

On Aug 13, 2:16 pm, Gautier <gaut...@fakeaddress.nil> wrote:
> Hello!
>
> In the procedure below, how to do [A] and [B] together, and is there a way not
> to have to write the constraints, like when constraining an object by
> initializing it with a value of the same type ?
>
> Thanks in advance!
> NB: I looked in a book, but maybe not hard enough ;-)
> -----
> procedure Test_Ancestor_copy is
>
>    type Index_array_type is array(Positive range <>) of Natural;
>
>    type PF_Data(
>      n1: Natural;
>      n2: Natural;
>      n3: Natural
>    )
>    is
>      tagged record
>        p1 : Index_array_type(1..n1);
>        p2 : Index_array_type(1..n2);
>        p3 : Index_array_type(1..n3);
>      end record;
>
>    function Read return PF_Data is
>    begin
>      return
>        (n1 => 1,
>         n2 => 2,
>         n3 => 3,
>         p1 => (1=>1),
>         p2 => (1,2),
>         p3 => (1,2,3)
>        );
>    end Read;
>
>    type PF is new PF_Data with record
>      computed: Boolean:= False;
>      result: Float;
>    end record;
>
>    initial_pf: constant PF_Data:= Read;
>
>    work_pf: PF(
>      n1 => initial_pf.n1,
>      n2 => initial_pf.n2,
>      n3 => initial_pf.n3
>    );
>    -- [A] work_pf sized with initial_pf constraints
>
> begin
>    PF_Data(work_pf):= initial_pf; -- [B] copy base data
> end;

My first thought (using Ada 2005) is

   work_pf : PF := (initial_pf with others => <>);

But I haven't looked through all the language rules to make sure this
is legal.

                      -- Adam