Re: [Vala] Is there any way to access generic type from the interface?

[Felipe Lavratti <felipelav gmail com>]

Even better, try this main instead the previous:

int main () {

    IMixinInterface fooer = new NothingSpecialFooer();
    fooer.foo();

    fooer = new TheSpecialFooer();
    fooer.foo();

    return 0;
}

Here we use the interface as the type of the object to show
polymorphism with mixin happening.

It prints:

$ ./test
** Message: test.vala:5: fooed defaulty!
** Message: test.vala:13: dummy string
** Message: test.vala:22: fooed specially!



On Sun, Feb 28, 2016 at 7:24 PM, Felipe Lavratti <felipelav gmail com> wrote:
> Right, I see what u are asking now.
>
> Well, if you want to do Mixins in Vala, you'll have to do the "static"
> workaround, since it doesn't support by default:
> https://wiki.gnome.org/Projects/Vala/Tutorial#Mixins_and_Multiple_Inheritanae
>
> Now you want to do Mixing with Generics? Ok, add the generic argument to
> each  Mixin method of your interface:
>
> public interface IMixinInterface : Object {
>     public abstract void foo();
>
>     public static T default_fooing<T>(T arg) {
>         GLib.message("fooed defaulty!");
>         return arg;
>     }
> }
>
> public abstract class BaseFooer : Object, IMixinInterface {
>     public virtual void foo() {
>         var dummy_string = IMixinInterface.default_fooing<string>("dummy
> string");
>         GLib.message(dummy_string);
>     }
> }
>
> public class NothingSpecialFooer : BaseFooer {
> }
>
> public class TheSpecialFooer : BaseFooer {
>     public override void foo() {
>         GLib.message("fooed specially!");
>     }
> }
>
> int main () {
>
>     var fooer = new NothingSpecialFooer();
>     fooer.foo();
>
>     var fooer2 = new TheSpecialFooer();
>     fooer2.foo();
>
>     return 0;
> }
>
>
> This example doesn't cover BaseFooer taking a generic argument, if the
> example is not enough, please provide me more details about how is the
> generic argument used in BaseFooer.
>
> - Fanl



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