On 18 Sep 2020, at 09:12, Albert Astals Cid via Development <[email protected]<mailto:[email protected]>> 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". The problem with the old comparisons was that it was rather random what compared to true and what compared to false. A bit like the much hated equality operator in JavaScript. We’ve basically now said, that (with some exceptions for pointers of related types and numerical types) that those will not compare equal. Is the official Qt position that we should all "copy&paste" QAbstractItemModelPrivate::isVariantLessThan into our item model classes that need sorting? Sorting and equality are two different things. QVariant has never supported a lessThan operator. Cheers, Lars Cheers, Albert -- Albert Astals Cid | [email protected]<mailto:[email protected]> | Senior Software Engineer Klarälvdalens Datakonsult AB, a KDAB Group company Tel: Sweden (HQ) +46-563-540090, USA +1-866-777-KDAB(5322) KDAB - The Qt, C++ and OpenGL Experts _______________________________________________ Development mailing list [email protected]<mailto:[email protected]> https://lists.qt-project.org/listinfo/development
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