On Sonntag, 19. April 2020 13:05:05 CEST André Pönitz wrote: > On Sat, Apr 18, 2020 at 09:44:40PM -0300, Thiago Macieira wrote: > > On Saturday, 18 April 2020 12:57:55 -03 Giuseppe D'Angelo via Interest wrote: > > > I guess that's the reason for dropping the comparisons in 6.0 and, > > > eventually, reintroduce it in 7.0. With the hope that we've learned the > > > lesson and proceed at _specifying_ the behaviour before implementing it. > > > > Indeed, and implement the QVariant comparator on top of each underlying > > type's spaceship operator. That way, we could order elements of the same > > type. For mismatched types, QVariant can return > > std::partial_ordering::unordered. > > > > We can't do that right now because we can't rely on C++20. In fact, no > > current compiler supports the spaceship operator. So that has to be Qt 7. > > How comes the spaceship operator comes into play here? > > It's syntactical sugar and in some cases an optimization, but has no > concepual powers exceeding those of operator<(). > It has the concept of weak ordering, it isn't just returning true or false, but an enum of a specific type, which so we can report two elements as incomparable if they are not of comparable types.
'Allan _______________________________________________ Interest mailing list Interest@qt-project.org https://lists.qt-project.org/listinfo/interest
