> People tend to use QList as a deque because of the fast prepend/take first
Simply, QArrayList should not be deprecated. It is also useful to store large objects that needs to be sorted. Philippe On Wed, 22 May 2019 18:25:18 +0200 ???? ?????????? <abba...@gmail.com> wrote: > 4. Use QVector to implement QList<Foo>, if sizeof(Foo) <= sizeof(quint64) and > Foo is movable > > > What about fast prepend in that case? People tend to use QList as a deque > because of the fast prepend/take first > > ???? ?????????? > > 22 ??? 2019 ?., ? 15:49, Lars Knoll <lars.kn...@qt.io> ???????(?): > > > Lets conclude the topic of QList. I do see the concern about silent source > breakages. Heres what well (Ill) do then for Qt 6: > > 1. Rename QList to QArrayList and make QList an alias to QArrayList > 2. Move QStringList and QByteArrayList over to inherit from QVector (that > should be source compatible) > 3. Rename QStringList to QStringVector (keep QStringList as a compatibility > name), same for QBAList > 4. Use QVector to implement QList<Foo>, if sizeof(Foo) <= sizeof(quint64) > and Foo is movable. Im intentionally not using sizeof(void *) here, as types > with sizes between 4 and 8 bytes would not have stable references in cross > platform code, so I do not believe lots of code would assume that (or it > would have broken on 64 bit). > 5. Add a compile time switch that allows mapping QList completely to QVector > or to a compatibility mode where QLists of large/non movable types are mapped > to QArrayList > 6. For now we dont yet want to explicitly change all our API that uses > QList to use QVector (as that would make merging from dev a pain, lets do > that later this year). But to test that everything we have works with > QVector, well set the compile switch to default to mapping to QVector. > 7. Make the implementation of QArrayList fully inline and deprecate the > class. > > Let me know if there are any major concerns with this plan. It should give > us a good compromise, where we can move all of Qt over to QVector and test > things early, as well as providing a compatibility mode for our users (slower > but wont silently break). > > Cheers, > Lars > > On 21 May 2019, at 10:38, Giuseppe D'Angelo via Development > <development@qt-project.org> wrote: > > Il 21/05/19 10:30, Konstantin Shegunov ha scritto: > That's a hard one. Especially since very few could keep in their brain a list > of the sizes of each and every one class from Qt. It also differs depending > on architecture. > > I know. That's my point: we can't just break this level of source > compatibility. > > Thanks, > > -- > Giuseppe D'Angelo | giuseppe.dang...@kdab.com | Senior Software Engineer > KDAB (France) S.A.S., a KDAB Group company > Tel. France +33 (0)4 90 84 08 53, http://www.kdab.com > KDAB - The Qt, C++ and OpenGL Experts > > _______________________________________________ > Development mailing list > Development@qt-project.org > https://lists.qt-project.org/listinfo/development > > _______________________________________________ > Development mailing list > Development@qt-project.org > https://lists.qt-project.org/listinfo/development > _______________________________________________ Development mailing list Development@qt-project.org https://lists.qt-project.org/listinfo/development
