Script prototype for value

[mjakubowski]

Hi,

I'm trying to pass my custom class, not based on QObject, to a script. I created a prototype that inherits from QScriptable, implemented all the properties and functions (as slots) I wanted, called Q_DECLARE_METATYPE and registered it to my QScriptEngine:

@PlanetPrototype planetPrototype = new PlanetPrototype;
QScriptValue planetProto = scriptEngine->newQObject(planetPrototype);
scriptEngine->setDefaultPrototype(qMetaTypeId<Planet>(), planetProto);@

So how do I now convert a Planet* to QScriptValue? If I do either of:
@engine->toScriptValue<Planet*>(myplanet);
engine->toObject(engine->toScriptValue<Planet*>(myplanet)@
the result is undefined in JavaScript.

Regards,
Marcin Jakubowski

[baysmith]

How does your code compare with the following?

@
#include <QtCore>
#include <QtScript/QtScript>

class Data
{
public:
Data() : _id("no-data"), _num(0) {}
Data(const QString &id, int num):
_id(id), _num(num)
{}

QString id() const { return _id; }
void setId(const QString& id) { _id = id; }

int num() const { return _num; }
void setNum(int num) { _num = num; }

private:
QString _id;
int _num;
};

Q_DECLARE_METATYPE(Data*)

class DataPrototype : public QObject, public QScriptable
{
Q_OBJECT
Q_PROPERTY(QString id READ id)
Q_PROPERTY(int num READ num)
public:
DataPrototype(QObject *parent = 0) : QObject(parent) {}

QString id() const
{
    Data *item = qscriptvalue_cast<Data*>(thisObject());
    if (item)
        return item->id();
    return "none";
}

int num() const
{
    Data *item = qscriptvalue_cast<Data*>(thisObject());
    if (item)
        return item->num();
    return 1;
}

};

int main(int argc, char *argv[])
{
QCoreApplication app(argc, argv);

QScriptEngine engine;

DataPrototype dataPrototype;
QScriptValue dataProto = engine.newQObject(&dataPrototype);
engine.setDefaultPrototype(qMetaTypeId<Data*>(), dataProto);

Data d("test", 7);
engine.globalObject().setProperty("d", engine.toScriptValue(&d));

QScriptValue result = engine.evaluate("d.id + ': ' + d.num");
qDebug() << result.toString();        // displays "test: 7"

QTimer::singleShot(1000, &app, SLOT(quit()));
return app.exec();

}

#include "main.moc"
@

[mjakubowski]

Seems correct to me, pretty much the same as yours:

@

Q_DECLARE_METATYPE(Planet*)

class PlanetPrototype : public QObject, public QScriptable
{
Q_OBJECT

Q_PROPERTY(QString id READ id)
Q_PROPERTY(QString name READ name)
Q_PROPERTY(int iCoords READ iCoords)
Q_PROPERTY(QString coords READ coords)

public:
PlanetPrototype(QObject *parent = 0);

QString id() const;
QString name() const;

int iCoords() const;
QString coords() const;

public slots:
int info(int id);

private:
Planet* thisPlanet() const;
};

// somewhere else

PlanetPrototype planetPrototype = new PlanetPrototype;
QScriptValue planetProto = scriptEngine->newQObject(planetPrototype);
qDebug() << qMetaTypeId<Planet>(); // is ok, returns 277

Planet *p = new Planet("test planet", "1000", PlanetCoords(1, 2, 3, 4, 5));
scriptEngine->globalObject().setProperty("myplanet", scriptEngine->toScriptValue(p));

scriptEngine->globalObject().setProperty("myplanet", scriptEngine->toScriptValue(p));
QScriptValue result = scriptEngine->evaluate("'givf object plx:' + myplanet");
qDebug() << result.toString(); // gives undefined

@

[mjakubowski]

Oh the stupidity.

@
QScriptValue result = scriptEngine->evaluate("'givf object plx:' + myplanet + ' - ' + myplanet.name");
qDebug() << result.toString(); // givf object plx:undefined - test planet
@

Although it seems strange that it says undefined even though it is not... I'm not an ECMAScript expert but I thought it should give me an Object.

[baysmith]

It says undefined because the toString() function is undefined for the prototype set for Planet*. If the setDefaultPrototype() on Planet* is not used, it would probably result in "givf object plx:QVariant(Planet*) - undefined". Define a toString() slot for the PlanetPrototype class and see how the result changes.

[mjakubowski]

Indeed, changes accordingly. Makes sense, thank you very much!