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=-0.3 required=5.0 tests=BAYES_00,
	REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: a07f3367d7,39579ad87542da0e
X-Google-Attributes: gida07f3367d7,public,usenet
X-Google-NewGroupId: yes
X-Google-Language: ENGLISH,ASCII-7-bit
X-Received: by 10.180.11.239 with SMTP id t15mr5471897wib.3.1369279581194;
        Wed, 22 May 2013 20:26:21 -0700 (PDT)
Path: 
 fw11ni1150wic.0!nntp.google.com!feeder1.cambriumusenet.nl!feed.tweaknews.nl!193.141.40.65.MISMATCH!npeer.de.kpn-eurorings.net!npeer-ng0.de.kpn-eurorings.net!border2.nntp.ams2.giganews.com!border4.nntp.ams.giganews.com!border2.nntp.ams.giganews.com!nntp.giganews.com!news.panservice.it!aioe.org!.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Seeking for papers about tagged types vs access to subprograms
Date: Thu, 16 May 2013 21:16:41 +0200
Organization: cbb software GmbH
Message-ID: <w1cs4nrk5j8e.dqwn69fc36xk.dlg@40tude.net>
References: <op.wv8jh1c1ule2fv@cardamome> <kmh7d4$up3$1@loke.gir.dk>
 <1oy5rmprgawqs.1jz36okze0xju$.dlg@40tude.net> <kmk45u$v45$1@loke.gir.dk>
 <1q2ql1e4rcgko.diszzq1mhaq8$.dlg@40tude.net>
 <518dedd4$0$6581$9b4e6d93@newsspool3.arcor-online.net>
 <hxkln519n179.1kt13z7phxg2f.dlg@40tude.net> <kms7hs$8ur$1@loke.gir.dk>
 <1um7tijeo609b$.1gtdijp0acfmn$.dlg@40tude.net> <op.ww2nq7t6ule2fv@cardamome>
 <mk9m6fxa1jbr$.mm0kw7g3igma$.dlg@40tude.net>
 <alpine.DEB.2.02.1305150714300.2254@whirlwind>
 <1nkyb845dehcu.1sd90udwsrpdu.dlg@40tude.net>
 <alpine.DEB.2.02.1305151601340.7888@whirlwind>
 <1mg9eepp12ood$.14lj7s8a7eygd$.dlg@40tude.net>
 <alpine.DEB.2.02.1305160641330.2594@whirlwind>
 <1cj8b5amtua30.1foe0rdpldt2.dlg@40tude.net>
 <alpine.DEB.2.02.1305160829510.2501@whirlwind>
 <lnx0yaymncw7$.pqorucpcq8r3$.dlg@40tude.net>
 <5195144f$0$6558$9b4e6d93@newsspool4.arcor-online.net>
 <alpine.DEB.2.02.1305161404190.3294@whirlwind>
Reply-To: mailbox@dmitry-kazakov.de
NNTP-Posting-Host: 15waz9CoS+eMakbyhTPyFQ.user.speranza.aioe.org
Mime-Version: 1.0
X-Complaints-To: abuse@aioe.org
User-Agent: 40tude_Dialog/2.0.15.1
X-Notice: Filtered by postfilter v. 0.8.2
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Date: 2013-05-16T21:16:41+02:00
List-Id: <comp.lang.ada>

On Thu, 16 May 2013 14:09:59 -0400, Peter C. Chapin wrote:

> On Thu, 16 May 2013, G.B. wrote:
> 
>> On 16.05.13 15:54, Dmitry A. Kazakov wrote:
> 
>>>> I realize that equivalence of functions is a difficult concept in general
>>> There is nothing difficult in that. A function is a set of pairs. Two sets
>>> are equal when contain same elements.
>>
>> I think the difficulty is that eq is not computable. For example,
>> if f1 and f2 are any Ada compilers, produce an algorithm that computes
>>
>>  eq(f1, f2)
>>
>> Then, proceed to finding eq of procedures computing eq.
> 
> The other problem with Dmitry's earlier suggestion is that the sets he's 
> talking about could be infinite in size (at least in principle).

Exactly, but it is a problem with your definition of value, not with mine. 

To me, as I said before, value does not belong to the language. Thus it is
not the language's problem to establish if two values are same. If the
programmer cares, he may declare operation "=" and implement it according
to the semantics of the problem space. If I wanted a type which values were
cardinal numbers aleph-0, aleph-1 etc, no problem with that.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de