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From: christoph.grein@eurocopter.com
Newsgroups: comp.lang.ada
Subject: Re: API design problem - buffer scatter I/O
Date: Mon, 24 Nov 2008 21:59:41 -0800 (PST)
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Date: 2008-11-24T21:59:41-08:00
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Thank you, Bob, for these illustrative comments. Problems with wiki is
that people with no good knowledge about the innards of a language
implementation may contribute (and I include myself into this class).

I fear you do not feel like correcting the wiki. I know, it's much
work, the whole chapter has to be rearranged.

> >...This is not an implementation
> > detail.
>
> Sure it is. =A0How a compiler represents data types (including access
> types) is an implementation detail.

What I meant is the incompatibility between pointers to constrained
and unconstrained:

type Unc     is array (Integer range <>) of Character;
type Acc_Unc is access Unc;

CO: aliased Unc (-1 .. +1) :=3D (-1 .. +1 =3D> ' ');
UO: aliased Unc            :=3D (-1 .. +1 =3D> ' ');

A: Acc_Unc            :=3D CO'Access;  -- illegal
B: Acc_Unc            :=3D UO'Access;  -- OK
C: Acc_Unc (CO'Range) :=3D CO'Access;  -- also illegal

which is not an implementation detail.