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  1. Qt
  2. QTBUG-71574

Provide a better way to register sequential and associative types for usage in QML

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    • d621027babff9a30d56ab6af871a465108c9eaba (qt/qtdeclarative/dev)

    Description

      At the moment all available sequence types are registered from qv4sequenceobject.cpp.

      qv4sequenceobject.cpp produces the largest single piece of binary code in Qt QML. It registers a variety of C++ containers as sequence objects to V4. For each combination of container and item type a few accessor functions have to be generated, leading to combinatorial explosion. In particular, the following types are registered:

      //  F(elementType, elementTypeName, sequenceType, defaultValue)
#define FOREACH_QML_SEQUENCE_TYPE(F) \
    F(int, IntVector, QVector<int>, 0) \
    F(qreal, RealVector, QVector<qreal>, 0.0) \
    F(bool, BoolVector, QVector<bool>, false) \
    F(int, IntStdVector, std::vector<int>, 0) \
    F(qreal, RealStdVector, std::vector<qreal>, 0.0) \
    F(bool, BoolStdVector, std::vector<bool>, false) \
    F(int, Int, QList<int>, 0) \
    F(qreal, Real, QList<qreal>, 0.0) \
    F(bool, Bool, QList<bool>, false) \
    F(QString, String, QList<QString>, QString()) \
    F(QString, QString, QStringList, QString()) \
    F(QString, StringVector, QVector<QString>, QString()) \
    F(QString, StringStdVector, std::vector<QString>, QString()) \
    F(QUrl, Url, QList<QUrl>, QUrl()) \
    F(QUrl, UrlVector, QVector<QUrl>, QUrl()) \
    F(QUrl, UrlStdVector, std::vector<QUrl>, QUrl()) \
    F(QModelIndex, QModelIndex, QModelIndexList, QModelIndex()) \
    F(QModelIndex, QModelIndexVector, QVector<QModelIndex>, QModelIndex()) \
    F(QModelIndex, QModelIndexStdVector, std::vector<QModelIndex>, QModelIndex()) \
    F(QItemSelectionRange, QItemSelectionRange, QItemSelection, QItemSelectionRange())

      Quite obviously, this list is rather arbitrary. Hardly anyone will use all of those, but some rather common ones are missing. For example there is no real reason why you wouldn't be able to pass a QList<QColor>.

      The fix to this involves three measures:

      1. Add public API to register your own container types as sequence objects via a template.
      2. Add a convenience wrapper around that to allow registering all the currently pre-registered sequence objects in one line in Qt6.
      3. Drop the pre-registering in Qt6.

      Attachments

        Issue Links

          is duplicated by

          Suggestion - Public suggestions QTBUG-75480 QML/C++ Conversions: Support more Lists, Maps and Hashes without QVariant

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed
          relates to

          Task - A task that needs to be done. QTBUG-68796 Create plugin.qmltypes automatically at build time

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Task - A task that needs to be done. QTBUG-79264 Provide a "lightweight model" template to mimic a key/value map

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          User Story - Created by Jira Software - do not edit or delete. Issue type for a user story. QTBUG-82443 Value types and Containers in QML

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Epic - Created by Jira Software - do not edit or delete. Issue type for a big user story that needs to be broken down. QTBUG-59971 Standard Library Type Support for QtQML

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed

          Task - A task that needs to be done. QTBUG-73399 Make it possible to use containered Q_GADGETS in QML

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Task - A task that needs to be done. QTBUG-79263 Provide a replace function for QQmlListProperty

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed
          split to

          Task - A task that needs to be done. QTBUG-121752 Add a way to register associative containers of object or value types

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Reported
          For Gerrit Dashboard: QTBUG-71574
          # Subject Branch Project Status CR V
          296890,7 Add QMetaContainer class dev qt/qtbase Status: ABANDONED -1 0
          313314,10 V4: Rewrite qv4sequenceobject based on QMetaSequence dev qt/qtdeclarative Status: MERGED +2 0

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              ulherman Ulf Hermann
              ulherman Ulf Hermann
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              Dates

                Created:
                Updated:
                Resolved:

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