On Thursday, 3 November 2022 09:48:49 PDT Marc Mutz via Development wrote: >>> Here, too, I feel lost. I'm struggling to see what a NIH >>> std::partial_ordering w/o the weak and strong counterparts and w/o >>> op<=> language support could achieve, except another vocabulary type >>> mismatch. Can you elaborate?
On 03.11.22 18:38, Thiago Macieira wrote: >> We can use it until we can depend on C++20. Like QSpan, that's why it's >> there. Marc Mutz (4 November 2022 11:22) > The difference is that QSpan vs. std::span doesn't create an impedance > mismatch. QPartialOrdering vs. std::partial_ordering does, esp. since > QPartialOrdering lacks an implicit conversion to/from > std::partial_ordering, and the member names are different. Since my comments on QDateTime are implicated here, I should note that - since it would be a behaviour change - an initial transition to a weak ordering that preserves invalid < valid could perfectly well suffice until we *do* transition to C++20 and *can* use std::partial_order, at which point I do think it would make sense to change our types with invalid (but supported) null-forms to make them incomparable, ideally all at the same time. > With the exception of qfloat32, I'm not aware of any Qt type that > would exhibit partial ordering semantics atm. I take it you mean qfloat16, whose NaN is incomparable, Eddy. _______________________________________________ Development mailing list Development@qt-project.org https://lists.qt-project.org/listinfo/development