On 18-09-2020 09:12, Albert Astals Cid via Development wrote:
El divendres, 18 de setembre de 2020, a les 2:54:53 CEST, Thiago Macieira va
escriure:
On Thursday, 17 September 2020 16:15:47 PDT Bernhard Lindner wrote:
Hi!
There was a discussion about the decision to deprecate (remove?) QVariant
comparison (<,>) in Qt6 completely.
Has anything changed for Qt6 (especially regarding comparison of equal
and/or convertible types)? Is the complete deprecation still the latest
decision?
Yes, it's changed; no, it's not deprecation.
What's been removed is the conversion. Aside from the numeric types,
comparing two variants of different types will always result in false. If
you want to compare across types, convert one to the other's type or to a
common third type. You know what data you put in there and you should know
what conversions can be lossy or not.
But i don't what data someone else put it in a QVariant.
The fact that QAbstractItemModelPrivate::isVariantLessThan exists should be
proof enough that you can't expect my class to know what someone else put
inside a QVariant, i mean that's basically the defining feature of QVariant "it
can hold random things for you".
Is the official Qt position that we should all "copy&paste"
QAbstractItemModelPrivate::isVariantLessThan into our item model classes that
need sorting?
How often do you really have items of different QVariant types in a
single column and and role in a model?
From what I understand, in Qt 6 you can still compare QVariants if they
contain the same type - be that a user type or not - for both equality
and lessThan provided the type in QVariant supports such comparisons. Right?
André
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