Re: [Vala] Invalid cast Warnings

[Daniel Brendle <grindhold skarphed org>]

On 02/05/2017 06:43 PM, Luca Dionisi wrote:
> Obviously you can't cast an instance of a base class to a superclass.
> You can do:
>  var a = new TestSubType();
>  TestBase b = (TestBase)a;
>
> Not viceversa.

What do you suggest as a pattern then for this scenario?
I want to extend the functionality of the library classes. Therefore I
should inherit from them. As it seems to me this is a valid OOP-style
endeavour.
But the library will only yield the objects it knows. I will never get
it to yield my subclassed objects. What mechanism do you suggest to use
to achieve this?

Thanks, Grindhold