Date/time class changes to handle extended date ranges

[Guillaume Laurent]

R.F. Pels wrote:
> If it is for a part in KDE or Qt that is widely used because it is something 
> very fundamental, yes, it is a big deal. And 'have to write at one time or 
> another' is not a very good argument for not considering giving the classes a 
> proper name. Giving those classes a proper name IS a big deal.
>   
I agree that breaking the Liskov Substitution Principle is a bad thing, 
but I don't think it applies here. QDate already has a 'isValid()' 
method, so no matter where a QDate comes from, you already know that you 
have to check for it's validity, i.e. that boilerplate code of yours has 
to be written anyway.