C++를 사용한 고급 QML 확장 기능 작성

class Person : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString name READ name WRITE setName NOTIFY nameChanged FINAL)
    Q_PROPERTY(int shoeSize READ shoeSize WRITE setShoeSize NOTIFY shoeSizeChanged FINAL)
    QML_ELEMENT
    ...
    QString m_name;
    int m_shoeSize = 0;
};

class BirthdayParty : public QObject
{
    Q_OBJECT
    Q_PROPERTY(Person *host READ host WRITE setHost NOTIFY hostChanged FINAL)
    Q_PROPERTY(QQmlListProperty<Person> guests READ guests NOTIFY guestsChanged FINAL)
    QML_ELEMENT
    ...
    Person *m_host = nullptr;
    QList<Person *> m_guests;
};

BirthdayParty {
    host: Person {
        name: "Bob Jones"
        shoeSize: 12
    }
    guests: [
        Person { name: "Leo Hodges" },
        Person { name: "Jack Smith" },
        Person { name: "Anne Brown" }
    ]
}

    QQmlEngine engine;
    QQmlComponent component(&engine);
    component.loadFromModule("People", "Main");
    std::unique_ptr<BirthdayParty> party{ qobject_cast<BirthdayParty *>(component.create()) };

"Bob Jones" is having a birthday!
They are inviting:
    "Leo Hodges"
    "Jack Smith"
    "Anne Brown"

class Boy : public Person
{
    Q_OBJECT
    QML_ELEMENT
public:
    using Person::Person;
};

class Girl : public Person
{
    Q_OBJECT
    QML_ELEMENT
public:
    using Person::Person;
};

class BirthdayParty : public QObject
{
    Q_OBJECT
    Q_PROPERTY(Person *host READ host WRITE setHost NOTIFY hostChanged FINAL)
    Q_PROPERTY(QQmlListProperty<Person> guests READ guests NOTIFY guestsChanged FINAL)
    QML_ELEMENT
    ...
};

class Person : public QObject
{
    ...
    QML_ELEMENT
    QML_UNCREATABLE("Person is an abstract base class.")
    ...
};

BirthdayParty {
    host: Boy {
        name: "Bob Jones"
        shoeSize: 12
    }
    guests: [
        Boy { name: "Leo Hodges" },
        Boy { name: "Jack Smith" },
        Girl { name: "Anne Brown" }
    ]
}

BirthdayParty {
    host: Boy {
        name: "Bob Jones"
        shoeSize: 12
    }

    Boy { name: "Leo Hodges" }
    Boy { name: "Jack Smith" }
    Girl { name: "Anne Brown" }
}

class BirthdayParty : public QObject
{
    Q_OBJECT
    Q_PROPERTY(Person *host READ host WRITE setHost NOTIFY hostChanged FINAL)
    Q_PROPERTY(QQmlListProperty<Person> guests READ guests NOTIFY guestsChanged FINAL)
    Q_CLASSINFO("DefaultProperty", "guests")
    QML_ELEMENT
    ...
};

class ShoeDescription : public QObject
{
    Q_OBJECT
    Q_PROPERTY(int size READ size WRITE setSize NOTIFY shoeChanged FINAL)
    Q_PROPERTY(QColor color READ color WRITE setColor NOTIFY shoeChanged FINAL)
    Q_PROPERTY(QString brand READ brand WRITE setBrand NOTIFY shoeChanged FINAL)
    Q_PROPERTY(qreal price READ price WRITE setPrice NOTIFY shoeChanged FINAL)
    ...
};

class Person : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString name READ name WRITE setName NOTIFY nameChanged FINAL)
    Q_PROPERTY(ShoeDescription *shoe READ shoe WRITE setShoe NOTIFY shoeChanged FINAL)
    ...
};

    Girl {
        name: "Anne Brown"
        shoe.size: 7
        shoe.color: "red"
        shoe.brand: "Job Macobs"
        shoe.price: 99.99
    }

    host: Boy {
        name: "Bob Jones"
        shoe { size: 12; color: "white"; brand: "Bikey"; price: 90.0 }
    }

class BirthdayPartyAttached : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QDate rsvp READ rsvp WRITE setRsvp NOTIFY rsvpChanged FINAL)
    QML_ANONYMOUS
    ...
};

class BirthdayParty : public QObject
{
    ...
    QML_ATTACHED(BirthdayPartyAttached)
    ...
    static BirthdayPartyAttached *qmlAttachedProperties(QObject *);

};

BirthdayParty {
    Boy {
        name: "Robert Campbell"
        BirthdayParty.rsvp: Date.fromLocaleString(Qt.locale(), "2023-03-01", "yyyy-MM-dd")
    }

    Boy {
        name: "Leo Hodges"
        shoe { size: 10; color: "black"; brand: "Reebok"; price: 59.95 }
        BirthdayParty.rsvp: Date.fromLocaleString(Qt.locale(), "2023-03-03", "yyyy-MM-dd")
    }

    host: Boy {
        name: "Jack Smith"
        shoe { size: 8; color: "blue"; brand: "Puma"; price: 19.95 }
    }
}

            QDate rsvpDate;
            QObject *attached = qmlAttachedPropertiesObject<BirthdayParty>(guest, false);

            if (attached)
                rsvpDate = attached->property("rsvp").toDate();

"Jack Smith" is having a birthday!
He is inviting:
    "Robert Campbell" RSVP date: "Wed Mar 1 2023"
    "Leo Hodges" RSVP date: "Mon Mar 6 2023"

class HappyBirthdaySong : public QObject, public QQmlPropertyValueSource
{
    Q_OBJECT
    Q_INTERFACES(QQmlPropertyValueSource)
    ...
    void setTarget(const QQmlProperty &) override;

};

BirthdayParty {
    id: party
    HappyBirthdaySong on announcement {
        name: party.host.name
    }
    ...
}

Happy birthday to you,
Happy birthday to you,
Happy birthday dear Bob Jones,
Happy birthday to you!

class Q_DECL_EXPORT ThirdPartyDisplay : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString content READ content WRITE setContent NOTIFY contentChanged FINAL)
    Q_PROPERTY(QColor foregroundColor READ foregroundColor WRITE setForegroundColor NOTIFY colorsChanged FINAL)
    Q_PROPERTY(QColor backgroundColor READ backgroundColor WRITE setBackgroundColor NOTIFY colorsChanged FINAL)
    ...
};

class ForeignDisplay : public QObject
{
    Q_OBJECT
    QML_NAMED_ELEMENT(ThirdPartyDisplay)
    QML_FOREIGN(ThirdPartyDisplay)
};

class BirthdayParty : public QObject
{
    Q_OBJECT
    Q_PROPERTY(Person *host READ host WRITE setHost NOTIFY hostChanged FINAL)
    Q_PROPERTY(QQmlListProperty<Person> guests READ guests NOTIFY guestsChanged FINAL)
    Q_PROPERTY(QString announcement READ announcement WRITE setAnnouncement NOTIFY announcementChanged FINAL)
    Q_PROPERTY(ThirdPartyDisplay *display READ display WRITE setDisplay NOTIFY displayChanged FINAL)
    ...
};

BirthdayParty {
    display: ThirdPartyDisplay {
        foregroundColor: "black"
        backgroundColor: "white"
    }
    ...
}

void BirthdayParty::setAnnouncement(const QString &announcement)
{
    if (m_announcement != announcement) {
        m_announcement = announcement;
        emit announcementChanged();
    }
    m_display->setContent(announcement);
}

[Fancy ThirdPartyDisplay] Happy birthday to you,
[Fancy ThirdPartyDisplay] Happy birthday to you,
[Fancy ThirdPartyDisplay] Happy birthday dear Bob Jones,
[Fancy ThirdPartyDisplay] Happy birthday to you!