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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: Encapsulating Ada.Direct_IO
Date: Wed, 17 Nov 2010 23:32:19 +0100
Organization: Ada @ Home
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Date: 2010-11-17T23:32:19+01:00
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Le Wed, 17 Nov 2010 05:44:49 +0100, Bryan <brobinson.eng@gmail.com> a  =

=C3=A9crit:
> Spec file:
> ...
> private
>   package Byte_IO is new Ada.Direct_IO(Character);
>   type File_Type is new Byte_IO.File_Type;
> end Big5_Text_IO;
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Why did you used a =E2=80=9Ctype new=E2=80=9D ? Unless you give some rea=
son, subtype is  =

better better here, as this avoid un-meaningful conversions every where.=
  =

If the type was defined in the public part, the type-new would have make=
  =

sense, but here it is defined in the private part, so no need to use  =

type-new, unless you want to attach it some special invariants which are=
  =

not part of the invariants of your Byte_IO.File_Type.

When you begin with Ada, you oftenly forget to make a good choice betwee=
n  =

type-new and subtype (probably because there is no such things with any =
 =

other language). Always balance type-new and subtype and don't  =

systematically use type-new all the way. Make choices with reasons.

-- =

Si les chats miaulent et font autant de vocalises bizarres, c=E2=80=99es=
t pas pour  =

les chiens.

=E2=80=9CI am fluent in ASCII=E2=80=9D [Warren 2010]