From: Aitor Alcrudo Sangros <aitor.alcrudo@gmail.com>
Subject: working with diferent instances of the same generic interface
Date: Tue, 8 Sep 2015 08:10:38 -0700 (PDT)
Date: 2015-09-08T08:10:38-07:00 [thread overview]
Message-ID: <625c79d2-f5ed-4cd4-80ea-ea310e381017@googlegroups.com> (raw)
Hi, my google-fu can't find how to do this. I think it should be doable but I'm not 100% sure. I'm thankful if anyone helps.
I have a generic interface some of my tagged records instance, similar to:
package Intro is
type Data_type is interface;
generic
type Readable_Data is abstract new Data_type with private;
package Readable is
type Readable_Element is interface;
type Readable_Element_Access is access all Readable_Element'Class ;
function Get_Values (this : Readable_Element ) return Readable_Data'Class
is abstract;
end Readable;
type state is (OK,KO);
generic
with package Readable_Reporting is new Readable(<>);
use Readable_Reporting ;
package Reporting is
type Reporting_Element is interface and Readable_Element ;
type Reporting_Element_Access is access all Reporting_Element'Class;
function Report (This :Reporting_Element ) return state is Abstract;
overriding function Get_Values (this : Reporting_Element ) return
Readable_Data'Class is abstract;
end Reporting;
end Intro;
This has worked with no problem.
I instance it like this
SomeData is new Data_type with record
a :float;
end record;
package Readable is new Intro.Readable(
readable_data =>SomeData);
package Reporting is new Intro.Reporting(Readable);
type Element_type_A is new Readable.Readable_Element
and Reporting.Reporting_Element
with record
data :float;
end record;
type Element_type_A_Access is access all Element_type_A 'Class;
Now, I have something like this
package Reporter is
package Readable_basic is new Intro.Readable(Data_type );
package Reporting_basic is new Intro.Reporting(Readable);
use Reporting;
type manager is tagged private;
procedure Add_Element( This : in out manager ;
Element : in Reporting_Element_Access );
private
package Element_Vector is new
Ada.Containers.Vectors (Natural,Reporting_Element_Access );
use Element_Vector ;
type manager is tagged record
Element_List : Element_Vector.Vector;
end record;
end Reporter ;
this compiles.
Now I try to use it elsewhere
procedure try is
man :manager ;
elm1 : Element_type_A_Access ;
elm2 : Element_type_B_Access ;
begin
man.add(Reporter.Reporting_basic.Reporting_Element_Access(elm1) );
man.add(Reporter.Reporting_basic.Reporting_Element_Access(elm2) );
end;
This compiles, but produces a runtime exception with invalid interface conversion.
Is there any way to get this to work?.
next reply other threads:[~2015-09-08 15:10 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-08 15:10 Aitor Alcrudo Sangros [this message]
2015-09-08 17:11 ` working with diferent instances of the same generic interface G.B.
2015-09-09 6:38 ` Jacob Sparre Andersen
2015-09-09 11:08 ` Aitor Alcrudo Sangros
2015-09-09 12:17 ` Egil H H
2015-09-09 12:41 ` Aitor Alcrudo Sangros
2015-09-09 13:10 ` Egil H H
2015-09-09 14:50 ` Aitor Alcrudo Sangros
2015-09-09 16:48 ` Egil H H
2015-09-09 19:04 ` Aitor Alcrudo Sangros
2015-09-09 19:16 ` Dmitry A. Kazakov
2015-10-01 16:45 ` Aitor Alcrudo Sangros
2015-10-01 19:29 ` Dmitry A. Kazakov
2015-10-01 20:09 ` Randy Brukardt
2015-09-13 18:22 ` Florian Weimer
2015-09-10 12:22 ` Jacob Sparre Andersen
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