QScriptClass Class Reference
[QtScript module]

Detailed Description

The QScriptClass class provides an interface for defining custom behavior of (a class of) Qt Script objects.

The QScriptClass class defines an interface for handling various aspects of interaction with the Qt Script objects associated with the class. Such objects are created by calling QScriptEngine::newObject(), passing a pointer to the QScriptClass as argument.

By subclassing QScriptClass, you can define precisely how access to properties of the objects that use your class is handled. This enables a fully dynamic handling of properties, e.g. it's more powerful than QScriptEngine::newQObject(). For example, you can use QScriptClass to implement array-type objects (i.e. objects that handle the length property, and properties whose names are valid array indexes, in a special way), or to implement a "live" (runtime-defined) proxy to an underlying object.

If you just need to handle access to a set of properties that are known at the time an object is created (i.e. "semi-statically"), you might consider using QScriptValue::setProperty() to define getter/setter functions for the relevant properties, rather than subclassing QScriptClass.

Reimplement queryProperty() to specify which properties are handled in a custom way by your script class (i.e. should be delegated to the QScriptClass), and which properties should be handled just like normal Qt Script object properties.

Reimplement property() and setProperty() to perform the actual access (read or write) to the properties that your class handles. Additionally, you can reimplement propertyFlags() to specify custom flags for your properties.

Reimplement newIterator() to provide an iterator for objects of your custom class. This is only necessary if objects of your class can have custom properties that you want to be reported when an object is used together with the QScriptValueIterator class, or when an object is used in a for-in enumeration statement in a script.

When implementing custom classes of objects, you typically use QScriptValue::setData() to store instance-specific data as part of object initialization; the data won't be accessible from scripts directly, but you can access it in e.g. your reimplementations of property() and setProperty() (by calling QScriptValue::data()) to perform custom processing.

Reimplement prototype() to provide a custom prototype object for your script class.

Reimplement supportsExtension() and extension() if your custom script class supports one or more of the extensions specified by the Extension enum.

See also QScriptClassPropertyIterator, QScriptEngine::newObject(), and Custom Script Class Example.

Member Type Documentation

 if (extension == Callable) {
     QScriptContext *context = qvariant_cast<QScriptContext*>(argument);
     QScriptEngine *engine = context->engine();
     double sum = 0;
     for (int i = 0; i < context->argumentCount(); ++i)
         sum += context->argument(i).toNumber();
     return sum;
 }