[fpc-devel] suggestion: virtual method co-variance

[Thaddy de Koning]

Isn't that exactly what is done in C++?
It is prepared in library code.

On 10/14/2014 12:40 PM, Marco van de Voort wrote:
> I recently had to dive a bit into C++ again, and reconnected with a feature
> I liked at first sight, the C++ covariance of virtual methods (changing the
> return type of a overriden method to a descendant of the original type).
> Googling a bit it seems that some languages(C#) also seem to allow this for
> parameters.  (not just return types)
>
> I suddenly wondered why it was never proposed or talked about  for FPC,
> since it seems such a nice feature.  Is there something particularly wrong
> with it?
>
> To a certain degree it can be emulated with generics, but that it
> requires a generic for every type, and must be prepared in the library code.
>
>
>
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