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From: hreba <hreba@terra.com.br>
Newsgroups: comp.lang.ada
Subject: Re: Generic Library Units?
Date: Sun, 12 Oct 2014 19:39:49 -0300
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Date: 2014-10-12T19:39:49-03:00
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On 10/12/2014 12:47 PM, Dmitry A. Kazakov wrote:
> On Sun, 12 Oct 2014 11:38:16 -0300, hreba wrote:
>
> A child of a generic package must be generic. I.e. you should declare it
> this way:
>
> generic
> package GuiGtk.SimpleGad is
>

Did that. And I added to Gui.ads the line

    with package TKSG is new GuiGtk.SimpleGad;

Now the line in mainaux.ads:

    package GuiTK is new Gui(Toolkit);

which was correct before, is accused:

mainaux.ads:10:04: missing actual "TKSG"
mainaux.ads:10:04: in instantiation of "Gui" declared at gui.ads:13

Adding
    package ToolkitSG is new GuiGtk.SimpleGad;
before that line gets me
mainaux.ads:9:29: invalid prefix in selected component "GuiGtk"

Replacing it with
    package ToolkitSG is new Toolkit.SimpleGad;
turns the error message into
mainaux.ads:9:36: generic child unit "SimpleGad" is not visible

So how do I instantiate that?

> And you will have to instantiate it somewhere.
>
> Generic packages are not suitable for abstraction GUI engines as complex as
> GTK or Qt. If you really want to use both GTK and Qt as the back-end, you
> should carefully design a set of abstract tagged types in several packages.
> GTK and Qt versions will derive from theses types.
>
I don't want to mix different toolkits. I want to have the same API in 
the case I switch to another one later.

-- 
Frank Hrebabetzky		+55 / 48 / 3235 1106
Florianopolis, Brazil