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From: "patrick.gunia@googlemail.com" <patrick.gunia@googlemail.com>
Newsgroups: comp.lang.ada
Subject: Re: Ada-Singleton-Why does it work like this?
Date: Wed, 25 Mar 2009 08:19:46 -0700 (PDT)
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> generic
> =A0 =A0type T2 (<>) is private; -- any type with or without discriminants
>
> Formally, T2 is declared to have "unknown discriminants". =A0This is
> also the case of the singleton type. Because, to the outside world, it
> has unknown discriminants, it is unconstrained. The full view of the
> type (in the private part of the package) may or may not specify
> discriminants.
>
> --
> Ludovic Brenta.

I think that this is what made me stumble. The fact that it simply
states, that it=B4s unknown wether or not the type has discriminants and
that the private part can or cannot use such discriminants. These are
concepts, I haven=B4t seen before when using other languages. And
because the package body knows the concrete structure of my
Singleton_Type, it also knows that a discriminant is not defined and
thus not necessary for creating new variables of my type. That is why I
=B4m able to create a Singleton instance within the package body. Is
this right? If so, then I finally got it...