[Development] Ideas for adding an argument with default value to a virtual method

[Stephen Kelly]

On Tuesday, January 24, 2012 20:36:53 Thiago Macieira wrote:
> On Tuesday, 24 de January de 2012 22.45.54, Stephen Kelly wrote:
> > I think it makes sense, but that is an often used and overridden virtual
> > method, and changing it would not make the compiler notify about the
> > porting  need (Can't expect downstream to be using Q_DECL_OVERRIDE
> > already).
> 
> Change the return value of the method that you don't want overridden to
> something completely different.
> 
> You cannot override a method with a non-covariant return type, so that will
> cause a compiler error and point to the change.

Yes, that's one of the things I tried:

On Tuesday, January 24, 2012 22:45:54 Stephen Kelly wrote:
> , and changing the return type 
> (success - clang gives an error for the derivation before porting).
> 
> In the cases where an error is given for the deriving code (before
> porting),  calling code still can't compile because the call is ambiguous
> anyway.

I would have to actually add new virtual methods with a new name instead of 
changing the parameters (and then call the old implementation from the old one 
- which would mean not deprecating the old one).

I'm not sure that's worth it. I also can't think of a more elegant solution, 
so I may just have to give up on it.

Thanks,

-- 
Stephen Kelly <stephen.kelly at kdab.com> | Software Engineer
KDAB (Deutschland) GmbH & Co.KG, a KDAB Group Company
www.kdab.com || Germany +49-30-521325470 || Sweden (HQ) +46-563-540090
KDAB - Qt Experts - Platform-Independent Software Solutions
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