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From: =?utf-8?Q?Yannick_Duch=C3=AAne_=28Hibou57?=
 =?utf-8?Q?=29?=
 <yannick_duchene@yahoo.fr>
Newsgroups: comp.lang.ada
Subject: Re: Seeking for papers about tagged types vs access to subprograms
Date: Tue, 30 Apr 2013 03:00:07 +0200
Organization: Ada @ Home
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Date: 2013-04-30T03:00:07+02:00
List-Id: <comp.lang.ada>

Le Tue, 30 Apr 2013 02:41:35 +0200, Shark8 <onewingedshark@gmail.com> a =
 =

=C3=A9crit:

> On Monday, April 29, 2013 6:31:37 PM UTC-6, Hibou57 (Yannick Duch=C3=AA=
ne)  =

> wrote:
>>
>> Same question in the context of `Ada.Finalization`. Similar semantic =
 =

>> could
>> have been made available without requiring tagged types.
>
> This is true; but it's likely that tagged-types were the easiest metho=
d  =

> to implement it.

I don't know if this was the easiest, but I personally feel this may be =
 =

was the option offering the biggest use=E2=80=91case coverage.

I though relying on tagged type allowed to be the most general as  =

possible. Defining an `Ada.Finalization` applicable to tagged types,  =

obviously requires tagged types. On the other hand, as what's not using =
 =

tagged type, may be redefined with little modification, to use tagged  =

types, using tagged types was the best option to cover the most general =
 =

case, even the ones not using tagged types in the first place.

However, tagged types may be excluded (ex. if there are proof  =

requirements) or not available (ex. the runtime in use does not support =
 =

it). That's a bit a pity to not be able to use something like  =

`Ada.Finalization` for applications not using tagged types. I even belie=
ve  =

`Ada.Finalization` is harder to avoid than tagged types  =

(`Ada.Finalization` looks more fundamental to me), especially that it  =

comes with added safety (as much as strong typing and ability to return =
 =

unconstrained types are).


-- =

=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