On 2017-03-24 20:55, Thiago Macieira wrote:
Em sexta-feira, 24 de março de 2017, às 09:18:05 PDT, Marc Mutz
escreveu:
> Are you of the opinion that private inheritance has no purpose and should
> never be used?
No, and if you look at code I have written over the years, you will
see that
I do use it.
One thing I've looked into in the past is this: Q6Polygon should
inherit a
Q6VectorBase<QPoint> that also Q6Vector<QPoint> inherits. This will
allow
easy specialisation of QVector<T*> by inheriting QBasicVector<const
void*>.
Can you elaborate on your thinking? What's QBasicVector and what's
QVector?
QBasicVector (or QVectorBase, or ...) is QVector with protection against
using it as-is (e.g. protected dtor). QVector inherits QBasicVector to
lift the restriction. This inheritance may even be public to avoid lots
of using QBasicVector::foo; This is ok, because QBasicVector is not
usable as-is, but I'd still make it private, because when you start to
inherit to specialise (QVector<T*> : QBasicVector<const void*>), you
don't want the void* methods to leak.
So, if you absolutely are set on inheritance, then use the same pattern.
But I don't see this here. None of the points that makes this a good
idea for QVector (or QVLA) pertains to QString: we don't need to fight
template bloat, we don't have multiple classes inheriting QStringView...
Thanks,
Marc
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