Why private methods cant be virtual?

Daniel Kozak kozzi11 at gmail.com
Tue Sep 22 13:19:10 UTC 2020

On Tue, Sep 22, 2020 at 3:05 PM claptrap via Digitalmars-d-learn <
digitalmars-d-learn at puremagic.com> wrote:

> The thread title is...
> "Why private methods cant be virtual?"
> IE Not...
> "how do I override private functions in a non-polymorphic manner."
> And what you suggest wont work because I was asking about virtual
> functions, so I specifically want polymorphism. And FWIW it's no
> big deal I can just use protected, i wasn't looking for a
> solution, I was looking for an explanation as to why it was done
> that way. But apparently there is none.
And I did not try to show solution. It was just an answer to this part of
your response:

So final private functions can be overriden? It seems not, but
the sentence is definitely confusing if not just plain wrong.

So the reason why there is this:

"Functions marked as final may not be overridden in a derived
 class, unless they are also private"

Is because with private methods final keyword has no meaning.

And there is a reason "Why private methods cant be virtual?".
It is because it would break existing code. And because  private methods
are final it makes them fast.
 And yes compiler probably could findout that method could be made
non-virtual but I am not sure how easy is this and how it would slow down
compilation times
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.puremagic.com/pipermail/digitalmars-d-learn/attachments/20200922/585829d2/attachment.htm>

More information about the Digitalmars-d-learn mailing list