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,FREEMAIL_FROM
	autolearn=ham autolearn_force=no version=3.4.4
X-Google-Thread: 103376,66fae8c862b81b17
X-Google-NewGroupId: yes
X-Google-Attributes: gida07f3367d7,domainid0,public,usenet
X-Google-Language: ENGLISH,UTF8
Received: by 10.180.84.74 with SMTP id w10mr4812992wiy.4.1352305074138;
        Wed, 07 Nov 2012 08:17:54 -0800 (PST)
Path: 
 ha8ni159560wib.1!nntp.google.com!feeder1.cambriumusenet.nl!feed.tweaknews.nl!194.134.4.91.MISMATCH!news2.euro.net!news.mixmin.net!aioe.org!.POSTED!not-for-mail
From: =?utf-8?Q?Yannick_Duch=C3=AAne_=28Hibou57?=
 =?utf-8?Q?=29?=
 <yannick_duchene@yahoo.fr>
Newsgroups: comp.lang.ada
Subject: Re: Copy vector in Ada
Date: Wed, 07 Nov 2012 17:17:51 +0100
Organization: Ada @ Home
Message-ID: <op.wnevj1xkule2fv@cardamome>
References: <1aWdnbcg_8-BzAzNnZ2dnUVZ_j6dnZ2d@giganews.com>
 <op.wm7f72j3ule2fv@cardamome>
 <6260a796-83c4-4ce5-88cb-8249846bc035@googlegroups.com>
 <10y91ckm54l57$.8u8bbq342u1b.dlg@40tude.net>
 <2164bc1a-a841-46ed-bfef-4ddcae4d64f7@googlegroups.com>
 <uti0vhlidr0b$.4tkmig1870rr$.dlg@40tude.net>
 <1ccf2169-418c-44b7-9d5a-b684a017fbe7@googlegroups.com>
 <1r3lpzblxy43h$.zytp8ur1bg27$.dlg@40tude.net> <op.wna877w8ule2fv@cardamome>
 <1k3sjasg1wftm$.1vlq5hm7vukhk.dlg@40tude.net> <op.wnbhcry0ule2fv@cardamome>
 <1sinhhpvja1gx.1ue7br8bz2slq$.dlg@40tude.net> <op.wnbkvsd6ule2fv@cardamome>
 <c308358c-e5bf-4bc1-a944-804499f26d13@googlegroups.com>
 <d7a2ef31-43f1-4000-af5a-d7414ec85b3f@googlegroups.com>
 <op.wnbxytxcule2fv@cardamome>
 <5098f58c$0$6558$9b4e6d93@newsspool4.arcor-online.net>
 <op.wndal8g5ule2fv@cardamome>
 <509a4dfb$0$6642$9b4e6d93@newsspool2.arcor-online.net>
 <trh6v6omvon9$.xacsgpq19lkv.dlg@40tude.net>
NNTP-Posting-Host: aWaWeUaBdaj2Zzc04J1v5A.user.speranza.aioe.org
Mime-Version: 1.0
X-Complaints-To: abuse@aioe.org
User-Agent: Opera Mail/12.02 (Linux)
X-Notice: Filtered by postfilter v. 0.8.2
Content-Type: text/plain; charset=utf-8; format=flowed; delsp=yes
Content-Transfer-Encoding: Quoted-Printable
Date: 2012-11-07T17:17:51+01:00
List-Id: <comp.lang.ada>

Le Wed, 07 Nov 2012 14:09:47 +0100, Dmitry A. Kazakov  =

<mailbox@dmitry-kazakov.de> a =C3=A9crit:

> On Wed, 07 Nov 2012 13:03:08 +0100, Georg Bauhaus wrote:
>
>> On 06.11.12 20:47, Yannick Duch=C3=AAne (Hibou57) wrote:
>>> Now, talking about proper naming of things, how would you explain to=
 a
>>> student, that sometime =E2=80=9Ctype=E2=80=9D must follow the substi=
tution principle,  =

>>> and
>>> sometime, it do exactly the opposite?
>>
>> The challenge is to explain why the substitution principle is
>> a valid commandment:
>
> It is not.
>
> Positive is a legitime subtype of Integer even though violates the LSP=
.

That's precisely what was said: both must not be confused.

> The valid proposition is that you should not substitute something
> non-substitutable, but you cannot enforce that through types. Correctn=
ess
> cannot be ensured through type checks.

Yes, but just like typing fails to ensure all of the correctness in the =
 =

large (and in some very few cases, even fails to accept valid things).  =

That's still the best balance we get between handy and safe.


-- =

=E2=80=9CSyntactic sugar causes cancer of the semi-colons.=E2=80=9D [1]
=E2=80=9CStructured Programming supports the law of the excluded muddle.=
=E2=80=9D [1]
[1]: Epigrams on Programming =E2=80=94 Alan J. =E2=80=94 P. Yale Univers=
ity