How to write gpr files from scratch , example 1, build only one package

How to write gpr files from scratch , example 1, build only one package

[Alain De Vos]

https://docs.adacore.com/gprbuild-docs/html/gprbuild_ug/gnat_project_manager.html

I have a file buttonhandler.adb containing :
-- TEST : Connecting via the On_* procedures first method
with GTk...stuff...;
package body buttonhandler is
   procedure On_Button_Click (Button : access Gtk_Button_Record'Class) is
   begin
      Put_line ("Hallo");
   end On_Button_Click;
end buttonhandler;
--------------------------------------------
> Now I write  : my_buttonhandler.gpr contents (as there is no main entry),                                              
with "gtkada.gpr";
project My_buttonhandler is
end My_buttonhandler;
------------------------------------------
Executing :
gprbuild -Pmy_buttonhandler.gpr returns :
Compile
   [Ada]          buttonhandler.adb
buttonhandler.adb:19:14: file "buttonhandler.ads" not found

Re: How to write gpr files from scratch , example 1, build only one package

[Alain De Vos]

On Friday, November 1, 2019 at 11:04:07 PM UTC+1, Alain De Vos wrote:
> https://docs.adacore.com/gprbuild-docs/html/gprbuild_ug/gnat_project_manager.html
> 
> I have a file buttonhandler.adb containing :
> -- TEST : Connecting via the On_* procedures first method
> with GTk...stuff...;
> package body buttonhandler is
>    procedure On_Button_Click (Button : access Gtk_Button_Record'Class) is
>    begin
>       Put_line ("Hallo");
>    end On_Button_Click;
> end buttonhandler;
> --------------------------------------------
> > Now I write  : my_buttonhandler.gpr contents (as there is no main entry),                                              
> with "gtkada.gpr";
> project My_buttonhandler is
> end My_buttonhandler;
> ------------------------------------------
> Executing :
> gprbuild -Pmy_buttonhandler.gpr returns :
> Compile
>    [Ada]          buttonhandler.adb
> buttonhandler.adb:19:14: file "buttonhandler.ads" not found

In C language you just compile all the object files and link them together but here it is bit different ...

Re: How to write gpr files from scratch , example 1, build only one package

[Dmitry A. Kazakov]

On 2019-11-01 23:10, Alain De Vos wrote:
> On Friday, November 1, 2019 at 11:04:07 PM UTC+1, Alain De Vos wrote:
>> https://docs.adacore.com/gprbuild-docs/html/gprbuild_ug/gnat_project_manager.html
>>
>> I have a file buttonhandler.adb containing :
>> -- TEST : Connecting via the On_* procedures first method
>> with GTk...stuff...;
>> package body buttonhandler is
>>     procedure On_Button_Click (Button : access Gtk_Button_Record'Class) is
>>     begin
>>        Put_line ("Hallo");
>>     end On_Button_Click;
>> end buttonhandler;

Apart from not having the package specification.

Text_IO is not the way to do it. A GTK application may have no standard 
output at all, e.g. under Windows you will see nothing.

Add a container Gtk_Grid or Gtk_Box to the top-level window. Put a 
Gtk_Button and a Gtk_Label there. Use Set_Text on the label from the 
button click callback.

You will see another problem immediately. The standard callback 
operations are useless most of the time because you need other 
parameters, like the container or the label.

See the package Gtk.Handlers how to create handlers with parameters, 
e.g. User_Callback in there.

For example:

    package Button_Handlers is
       new Gtk.Handlers.User_Callback (Gtk_Button_Record, Gtk_Label);

Then

    procedure On_Button_Click
              (  Button : access Gtk_Button_Record'Class;
                 Label  : Gtk_Label
              )  is
   begin
      Label.Set_Text ("Hallo");
   end On_Button_Click;

Connecting to the signal goes as follows:

    Button_Handlers.Connect
    (  Button,
       "clicked",
       On_Button_Click'Access,
       Label
    );

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

Re: How to write gpr files from scratch , example 1, build only one package

[Simon Wright]

Alain De Vos <devosalain71@gmail.com> writes:

> buttonhandler.adb:19:14: file "buttonhandler.ads" not found

Perhaps the reason for the compiler not finding this file is that you
haven't written it.

Re: How to write gpr files from scratch , example 1, build only one package

[Alain De Vos]

On Friday, November 1, 2019 at 11:26:13 PM UTC+1, Simon Wright wrote:
> Alain De Vos <devosalain71@gmail.com> writes:
> 
> > buttonhandler.adb:19:14: file "buttonhandler.ads" not found
> 
> Perhaps the reason for the compiler not finding this file is that you
> haven't written it.

The line 19 is :
package body buttonhandler is 

Maybe i missed something ?

Re: How to write gpr files from scratch , example 1, build only one package

[Alain De Vos]

On Friday, November 1, 2019 at 11:33:24 PM UTC+1, Alain De Vos wrote:
> On Friday, November 1, 2019 at 11:26:13 PM UTC+1, Simon Wright wrote:
> > Alain De Vos <devosalain71@gmail.com> writes:
> > 
> > > buttonhandler.adb:19:14: file "buttonhandler.ads" not found
> > 
> > Perhaps the reason for the compiler not finding this file is that you
> > haven't written it.
> 
> The line 19 is :
> package body buttonhandler is 
> 
> Maybe i missed something ?

give me a minute :)

Re: How to write gpr files from scratch , example 1, build only one package

[Alain De Vos]

On Friday, November 1, 2019 at 11:34:27 PM UTC+1, Alain De Vos wrote:
> On Friday, November 1, 2019 at 11:33:24 PM UTC+1, Alain De Vos wrote:
> > On Friday, November 1, 2019 at 11:26:13 PM UTC+1, Simon Wright wrote:
> > > Alain De Vos <devosalain71@gmail.com> writes:
> > > 
> > > > buttonhandler.adb:19:14: file "buttonhandler.ads" not found
> > > 
> > > Perhaps the reason for the compiler not finding this file is that you
> > > haven't written it.
> > 
> > The line 19 is :
> > package body buttonhandler is 
> > 
> > Maybe i missed something ?
> 
> give me a minute :)

Writing an ads files solved the problem.

Re: How to write gpr files from scratch , example 1, build only one package

[Dennis Lee Bieber]

On Fri, 1 Nov 2019 15:33:22 -0700 (PDT), Alain De Vos
<devosalain71@gmail.com> declaimed the following:

>On Friday, November 1, 2019 at 11:26:13 PM UTC+1, Simon Wright wrote:
>> Alain De Vos <devosalain71@gmail.com> writes:
>> 
>> > buttonhandler.adb:19:14: file "buttonhandler.ads" not found
>> 
>> Perhaps the reason for the compiler not finding this file is that you
>> haven't written it.
>
>The line 19 is :
>package body buttonhandler is 
>
>Maybe i missed something ?

	That defines a BODY file. It is not a SPECification file (.ads).

	The spec file defines the interface -- what objects and methods are
available to users of the package.


-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
	wlfraed@ix.netcom.com    http://wlfraed.microdiversity.freeddns.org/

Re: How to write gpr files from scratch , example 1, build only one package

[Alain De Vos]

On Friday, November 1, 2019 at 11:04:07 PM UTC+1, Alain De Vos wrote:
> https://docs.adacore.com/gprbuild-docs/html/gprbuild_ug/gnat_project_manager.html
> 
> I have a file buttonhandler.adb containing :
> -- TEST : Connecting via the On_* procedures first method
> with GTk...stuff...;
> package body buttonhandler is
>    procedure On_Button_Click (Button : access Gtk_Button_Record'Class) is
>    begin
>       Put_line ("Hallo");
>    end On_Button_Click;
> end buttonhandler;
> --------------------------------------------
> > Now I write  : my_buttonhandler.gpr contents (as there is no main entry),                                              
> with "gtkada.gpr";
> project My_buttonhandler is
> end My_buttonhandler;
> ------------------------------------------
> Executing :
> gprbuild -Pmy_buttonhandler.gpr returns :
> Compile
>    [Ada]          buttonhandler.adb
> buttonhandler.adb:19:14: file "buttonhandler.ads" not found

Yes gtk.handlers are the way to go, but one step at a time, I come that later. 
I order not not clutter I post a new specific question regarding the on_procedure method.