Re: [Vala] Another interface implementation problem

[Jürg Billeter <j bitron ch>]

Hi Dominique,

On Sam, 2006-09-02 at 18:38 +0200, Dominique Würtz wrote:
> I'm struggling with the following hierarchy provided by GooCanvas (which 
> I'm creating bindings for):
>
> interface Item {
>     public abstract View create_view ();
> }
>
> abstract class SimpleItem : Item {
>     // This does _not_ implement create_view ()
> }
>
> class MyItem : SimpleItem {
>     public override View create_view ();
> }
>
> Vala complains that it can't find I prototype for create_view () in 
> SimpleItem which can be overridden. Out of curiosity I fed this 
> hierarchy into the Mono C# compiler and found that C# requires you to 
> implement the complete interface in SimpleItem. However, GooCanvas 
> relies on these relaxed inheritance policies, so my question is, could 
> Vala be modified to accept abstract classes implementing interfaces only 
> partly?

Yes, it makes sense to add this functionality to Vala. There is an easy
workaround available if you only need it in bindings at the moment: You
can just remove the overriding method from the VAPI file as the compiler
doesn't really care which classes override which methods in bindings.

Jürg