Re: Generic Library Units?

[hreba <hreba@terra.com.br>]

On 10/15/2014 04:21 AM, Dmitry A. Kazakov wrote:
> On Tue, 14 Oct 2014 21:29:16 -0300, hreba wrote:
>
>> On 10/13/2014 04:45 AM, Dmitry A. Kazakov wrote:
>>>
>>> with Gui;
>>> with GuiGtk.SimpleGad;
>>> with Gui.SimpleGad;
>>> package MainAux is
>>>       package Toolkit is new GuiGtk;
>>>       package SimpleGad is new Toolkit.SimpleGad;
>>>       package GuiTK is new Gui (Toolkit, SimpleGad);
>>> end MainAux;
>>>
>> Ok, did that too, and the error message disappeared.
>>
>> Now in the package body of Gui.SimpleGad I have
>>
>>      function Get (gad: BoolGadget) return boolean is
>>      begin
>>         return TKSG.GetBool (gad.widget.all);
>>      end Get;
>>
>> and get the error message
>>
>> gui-simplegad.adb:78:39: expected type "GuiGtk.GadWidgets" defined at
>> guigtk.ads:38
>> gui-simplegad.adb:78:39: found type "TK.GadWidgets" defined at
>> guigtk.ads:38, instance at gui.ads:10
>>
>> So the compiler isn't aware that GuiGtk is the actual value to the
>> formal package TK. How do I tell him?
>
> You can't. GuiGtk is a generic package. It cannot be actual of anything.
> Actuals are *real* things. E.g. an instance of a generic package can be
> actual of a formal package.
>
>> ( The Gui package header is
>>
>>      generic
>>         with package TK is new GuiGtk(<>);	-- this is gui.ads:10
>>         with package TKSG is new GuiGtk.SimpleGad;
>>      package Gui is
>>      ...
>> )
>
> Which has nothing to do with GuiGtk and GuiGtk.SimpleGad. Generic packages
> know nothing about any instances of. That is the basic idea of being
> "generic".
>

Basically I only need type and subprogram parameters for my generic 
package Gui (and Gui.SimpleGad) package.
As I have dozens of subprogram parameters, I packed them (together with 
the types) into a package parameter GuiGtk and it worked. It didn't work 
anymore when I outsourced part of GuiGtk into GuiGtk.SimpleGad.

 From what you say I understand that there is no cure, so I will stick 
to a GuiGtk without a child package.

Thanks for the hints.
-- 
Frank Hrebabetzky		+55 / 48 / 3235 1106
Florianopolis, Brazil