path: root/doc/src/snippets/code/doc_src_qtscript.qdoc

//! [0]
#include <QtScript>
//! [0]


//! [1]
QT += script
//! [1]


//! [2]
function myInterestingScriptFunction() { ... }
...
myQObject.somethingChanged.connect(myInterestingScriptFunction);
//! [2]


//! [3]
myQObject.somethingChanged.connect(myOtherQObject.doSomething);
//! [3]


//! [4]
myQObject.somethingChanged.disconnect(myInterestingFunction);
myQObject.somethingChanged.disconnect(myOtherQObject.doSomething);
//! [4]


//! [5]
var obj = { x: 123 };
var fun = function() { print(this.x); };
myQObject.somethingChanged.connect(obj, fun);
//! [5]


//! [6]
myQObject.somethingChanged.disconnect(obj, fun);
//! [6]


//! [7]
var obj = { x: 123, fun: function() { print(this.x); } };
myQObject.somethingChanged.connect(obj, "fun");
//! [7]


//! [8]
myQObject.somethingChanged.disconnect(obj, "fun");
//! [8]


//! [9]
try {
    myQObject.somethingChanged.connect(myQObject, "slotThatDoesntExist");
} catch (e) {
    print(e);
}
//! [9]


//! [10]
myQObject.somethingChanged("hello");
//! [10]


//! [11]
myQObject.myOverloadedSlot(10);   // will call the int overload
myQObject.myOverloadedSlot("10"); // will call the QString overload
//! [11]


//! [12]
myQObject['myOverloadedSlot(int)']("10");   // call int overload; the argument is converted to an int
myQObject['myOverloadedSlot(QString)'](10); // call QString overload; the argument is converted to a string
//! [12]


//! [13]
Q_PROPERTY(bool enabled READ enabled WRITE setEnabled)
//! [13]


//! [14]
myQObject.enabled = true;

...

myQObject.enabled = !myQObject.enabled;
//! [14]


//! [15]
myDialog.okButton
//! [15]


//! [16]
myDialog.okButton.objectName = "cancelButton";
// from now on, myDialog.cancelButton references the button
//! [16]


//! [17]
var okButton = myDialog.findChild("okButton");
if (okButton != null) {
   // do something with the OK button
}

var buttons = myDialog.findChildren(RegExp("button[0-9]+"));
for (var i = 0; i < buttons.length; ++i) {
   // do something with buttons[i]
}
//! [17]


//! [18]
QScriptValue myQObjectConstructor(QScriptContext *context, QScriptEngine *engine)
{
  // let the engine manage the new object's lifetime.
  return engine->newQObject(new MyQObject(), QScriptEngine::ScriptOwnership);
}
//! [18]


//! [19]
class MyObject : public QObject
{
    Q_OBJECT

public:
    MyObject( ... );

    void aNonScriptableFunction();

public slots: // these functions (slots) will be available in QtScript
    void calculate( ... );
    void setEnabled( bool enabled );
    bool isEnabled() const;

private:
   ....

};
//! [19]


//! [20]
class MyObject : public QObject
{
    Q_OBJECT

    public:
    Q_INVOKABLE void thisMethodIsInvokableInQtScript();
    void thisMethodIsNotInvokableInQtScript();

    ...
};
//! [20]


//! [21]
var obj = new MyObject;
obj.setEnabled( true );
print( "obj is enabled: " + obj.isEnabled() );
//! [21]


//! [22]
var obj = new MyObject;
obj.enabled = true;
print( "obj is enabled: " + obj.enabled );
//! [22]


//! [23]
class MyObject : public QObject
{
    Q_OBJECT
    // define the enabled property
    Q_PROPERTY( bool enabled WRITE setEnabled READ isEnabled )

public:
    MyObject( ... );

    void aNonScriptableFunction();

public slots: // these functions (slots) will be available in QtScript
    void calculate( ... );
    void setEnabled( bool enabled );
    bool isEnabled() const;

private:
   ....

};
//! [23]


//! [24]
Q_PROPERTY(int nonScriptableProperty READ foo WRITE bar SCRIPTABLE false)
//! [24]


//! [25]
class MyObject : public QObject
{
    Q_OBJECT
    // define the enabled property
    Q_PROPERTY( bool enabled WRITE setEnabled READ isEnabled )

public:
    MyObject( ... );

    void aNonScriptableFunction();

public slots: // these functions (slots) will be available in QtScript
    void calculate( ... );
    void setEnabled( bool enabled );
    bool isEnabled() const;

signals: // the signals
    void enabledChanged( bool newState );

private:
   ....

};
//! [25]


//! [26]
function enabledChangedHandler( b )
{
    print( "state changed to: " + b );
}

function init()
{
    var obj = new MyObject();
    // connect a script function to the signal
    obj["enabledChanged(bool)"].connect(enabledChangedHandler);
    obj.enabled = true;
    print( "obj is enabled: " + obj.enabled );
}
//! [26]


//! [27]
var o = new Object();
o.foo = 123;
print(o.hasOwnProperty('foo')); // true
print(o.hasOwnProperty('bar')); // false
print(o); // calls o.toString(), which returns "[object Object]"
//! [27]


//! [28]
function Person(name)
{
  this.name = name;
}
//! [28]


//! [29]
Person.prototype.toString = function() { return "Person(name: " + this.name + ")"; }
//! [29]


//! [30]
var p1 = new Person("John Doe");
var p2 = new Person("G.I. Jane");
print(p1); // "Person(name: John Doe)"
print(p2); // "Person(name: G.I. Jane)"
//! [30]


//! [31]
print(p1.hasOwnProperty('name')); // 'name' is an instance variable, so this returns true
print(p1.hasOwnProperty('toString')); // returns false; inherited from prototype
print(p1 instanceof Person); // true
print(p1 instanceof Object); // true
//! [31]


//! [32]
function Employee(name, salary)
{
  Person.call(this, name); // call base constructor

  this.salary = salary;
}

// set the prototype to be an instance of the base class
Employee.prototype = new Person();

// initialize prototype
Employee.prototype.toString = function() { ... }
//! [32]


//! [33]
var e = new Employee("Johnny Bravo", 5000000);
print(e instanceof Employee); // true
print(e instanceof Person);   // true
print(e instanceof Object);   // true
print(e instanceof Array);    // false
//! [33]


//! [34]
QScriptValue Person_ctor(QScriptContext *context, QScriptEngine *engine)
{
  QString name = context->argument(0).toString();
  context->thisObject().setProperty("name", name);
  return engine->undefinedValue();
}
//! [34]


//! [35]
QScriptValue Person_prototype_toString(QScriptContext *context, QScriptEngine *engine)
{
  QString name = context->thisObject().property("name").toString();
  QString result = QString::fromLatin1("Person(name: %0)").arg(name);
  return result;
}
//! [35]


//! [36]
QScriptEngine engine;
QScriptValue ctor = engine.newFunction(Person_ctor);
ctor.property("prototype").setProperty("toString", engine.newFunction(Person_prototype_toString));
QScriptValue global = engine.globalObject();
global.setProperty("Person", ctor);
//! [36]


//! [37]
QScriptValue Employee_ctor(QScriptContext *context, QScriptEngine *engine)
{
  QScriptValue super = context->callee().property("prototype").property("constructor");
  super.call(context->thisObject(), QScriptValueList() << context->argument(0));
  context->thisObject().setProperty("salary", context->argument(1));
  return engine->undefinedValue();
}
//! [37]


//! [38]
QScriptValue empCtor = engine.newFunction(Employee_ctor);
empCtor.setProperty("prototype", global.property("Person").construct());
global.setProperty("Employee", empCtor);
//! [38]


//! [39]
Q_DECLARE_METATYPE(QPointF)
Q_DECLARE_METATYPE(QPointF*)

QScriptValue QPointF_prototype_x(QScriptContext *context, QScriptEngine *engine)
{
  // Since the point is not to be modified, it's OK to cast to a value here
    QPointF point = qscriptvalue_cast<QPointF>(context->thisObject());
    return point.x();
}

QScriptValue QPointF_prototype_setX(QScriptContext *context, QScriptEngine *engine)
{
    // Cast to a pointer to be able to modify the underlying C++ value
    QPointF *point = qscriptvalue_cast<QPointF*>(context->thisObject());
    if (!point)
        return context->throwError(QScriptContext::TypeError, "QPointF.prototype.setX: this object is not a QPointF");
    point->setX(context->argument(0).toNumber());
    return engine->undefinedValue();
}
//! [39]


//! [40]
var o = new Object();
(o.__proto__ === Object.prototype); // this evaluates to true
//! [40]


//! [41]
var o = new Object();
o.__defineGetter__("x", function() { return 123; });
var y = o.x; // 123
//! [41]


//! [42]
var o = new Object();
o.__defineSetter__("x", function(v) { print("and the value is:", v); });
o.x = 123; // will print "and the value is: 123"
//! [42]


//! [43]
class MyObject : public QObject
{
    Q_OBJECT
    ...
};

Q_DECLARE_METATYPE(MyObject*)

QScriptValue myObjectToScriptValue(QScriptEngine *engine, MyObject* const &in)
{ return engine->newQObject(in); }

void myObjectFromScriptValue(const QScriptValue &object, MyObject* &out)
{ out = qobject_cast<MyObject*>(object.toQObject()); }

...

qScriptRegisterMetaType(&engine, myObjectToScriptValue, myObjectFromScriptValue);
//! [43]

//! [44]
QScriptValue QPoint_ctor(QScriptContext *context, QScriptEngine *engine)
{
    int x = context->argument(0).toInt32();
    int y = context->argument(1).toInt32();
    return engine->toScriptValue(QPoint(x, y));
}

...

engine.globalObject().setProperty("QPoint", engine.newFunction(QPoint_ctor));
//! [44]

//! [45]
QScriptValue myPrintFunction(QScriptContext *context, QScriptEngine *engine)
{
    QString result;
    for (int i = 0; i < context->argumentCount(); ++i) {
        if (i > 0)
            result.append(" ");
        result.append(context->argument(i).toString());
    }

    QScriptValue calleeData = context->callee().data();
    QPlainTextEdit *edit = qobject_cast<QPlainTextEdit*>(calleeData.toQObject());
    edit->appendPlainText(result);

    return engine->undefinedValue();
}
//! [45]

//! [46]
int main(int argc, char **argv)
{
    QApplication app(argc, argv);

    QScriptEngine eng;
    QPlainTextEdit edit;

    QScriptValue fun = eng.newFunction(myPrintFunction);
    fun.setData(eng.newQObject(&edit));
    eng.globalObject().setProperty("print", fun);

    eng.evaluate("print('hello', 'world')");

    edit.show();
    return app.exec();
}
//! [46]


//! [47]
QScriptEngine eng;
QLineEdit *edit = new QLineEdit(...);
QScriptValue handler = eng.evaluate("function(text) { print('text was changed to', text); }");
qScriptConnect(edit, SIGNAL(textChanged(const QString &)), QScriptValue(), handler);
//! [47]

//! [48]
QLineEdit *edit1 = new QLineEdit(...);
QLineEdit *edit2 = new QLineEdit(...);

QScriptValue handler = eng.evaluate("function() { print('I am', this.name); }");
QScriptValue obj1 = eng.newObject();
obj1.setProperty("name", "the walrus");
QScriptValue obj2 = eng.newObject();
obj2.setProperty("name", "Sam");

qScriptConnect(edit1, SIGNAL(returnPressed()), obj1, handler);
qScriptConnect(edit2, SIGNAL(returnPressed()), obj2, handler);
//! [48]

//! [49]
var getProperty = function(name) { return this[name]; };

name = "Global Object"; // creates a global variable
print(getProperty("name")); // "Global Object"

var myObject = { name: 'My Object' };
print(getProperty.call(myObject, "name")); // "My Object"

myObject.getProperty = getProperty;
print(myObject.getProperty("name")); // "My Object"

getProperty.name = "The getProperty() function";
getProperty.getProperty = getProperty;
getProperty.getProperty("name"); // "The getProperty() function"
//! [49]

//! [50]
var o = { a: 1, b: 2, sum: function() { return a + b; } };
print(o.sum()); // reference error, or sum of global variables a and b!!
//! [50]

//! [51]
var o = { a: 1, b: 2, sum: function() { return this.a + this.b; } };
print(o.sum()); // 3
//! [51]

//! [52]
QScriptValue getProperty(QScriptContext *ctx, QScriptEngine *eng)
{
    QString name = ctx->argument(0).toString();
    return ctx->thisObject().property(name);
}
//! [52]

//! [53]
QScriptValue myCompare(QScriptContext *ctx, QScriptEngine *eng)
{
    double first = ctx->argument(0).toNumber();
    double second = ctx->argument(1).toNumber();
    int result;
    if (first == second)
        result = 0;
    else if (first < second)
        result = -1;
    else
        result = 1;
    return result;
}
//! [53]

//! [54]
QScriptEngine eng;
QScriptValue comparefn = eng.newFunction(myCompare);
QScriptValue array = eng.evaluate("new Array(10, 5, 20, 15, 30)");
array.property("sort").call(array, QScriptValueList() << comparefn);

// prints "5,10,15,20,30"
qDebug() << array.toString();
//! [54]

//! [55]
QScriptValue rectifier(QScriptContext *ctx, QScriptEngine *eng)
{
    QRectF magicRect = qscriptvalue_cast<QRectF>(ctx->callee().data());
    QRectF sourceRect = qscriptvalue_cast<QRectF>(ctx->argument(0));
    return eng->toScriptValue(sourceRect.intersected(magicRect));
}

...

QScriptValue fun = eng.newFunction(rectifier);
QRectF magicRect = QRectF(10, 20, 30, 40);
fun.setData(eng.toScriptValue(magicRect));
eng.globalObject().setProperty("rectifier", fun);
//! [55]

//! [56]
function add(a, b) {
    return a + b;
}
//! [56]

//! [57]
function add() {
    return arguments[0] + arguments[1];
}
//! [57]

//! [58]
QScriptValue add(QScriptContext *ctx, QScriptEngine *eng)
{
    double a = ctx->argument(0).toNumber();
    double b = ctx->argument(1).toNumber();
    return a + b;
}
//! [58]

//! [59]
function add() {
    if (arguments.length != 2)
        throw Error("add() takes exactly two arguments");
    return arguments[0] + arguments[1];
}
//! [59]

//! [60]
function add() {
    if (arguments.length != 2)
        throw Error("add() takes exactly two arguments");
    if (typeof arguments[0] != "number")
        throw TypeError("add(): first argument is not a number");
    if (typeof arguments[1] != "number")
        throw TypeError("add(): second argument is not a number");
    return arguments[0] + arguments[1];
}
//! [60]

//! [61]
function add() {
    if (arguments.length != 2)
        throw Error("add() takes exactly two arguments");
    return Number(arguments[0]) + Number(arguments[1]);
}
//! [61]

//! [62]
QScriptValue add(QScriptContext *ctx, QScriptEngine *eng)
{
    if (ctx->argumentCount() != 2)
        return ctx->throwError("add() takes exactly two arguments");
    double a = ctx->argument(0).toNumber();
    double b = ctx->argument(1).toNumber();
    return a + b;
}
//! [62]

//! [63]
QScriptValue add(QScriptContext *ctx, QScriptEngine *eng)
{
    if (ctx->argumentCount() != 2)
        return ctx->throwError("add() takes exactly two arguments");
    if (!ctx->argument(0).isNumber())
        return ctx->throwError(QScriptContext::TypeError, "add(): first argument is not a number");
    if (!ctx->argument(1).isNumber())
        return ctx->throwError(QScriptContext::TypeError, "add(): second argument is not a number");
    double a = ctx->argument(0).toNumber();
    double b = ctx->argument(1).toNumber();
    return a + b;
}
//! [63]

//! [64]
function concat() {
    var result = "";
    for (var i = 0; i < arguments.length; ++i)
        result += String(arguments[i]);
    return result;
}
//! [64]

//! [65]
QScriptValue concat(QScriptContext *ctx, QScriptEngine *eng)
{
    QString result = "";
    for (int i = 0; i < ctx->argumentCount(); ++i)
        result += ctx->argument(i).toString();
    return result;
}
//! [65]

//! [66]
function sort(comparefn) {
    if (comparefn == undefined)
        comparefn = /* the built-in comparison function */;
    else if (typeof comparefn != "function")
        throw TypeError("sort(): argument must be a function");
    ...
}
//! [66]

//! [67]
QScriptValue sort(QScriptContext *ctx, QScriptEngine *eng)
{
    QScriptValue comparefn = ctx->argument(0);
    if (comparefn.isUndefined())
        comparefn = /* the built-in comparison function */;
    else if (!comparefn.isFunction())
        return ctx->throwError(QScriptContext::TypeError, "sort(): argument is not a function");
    ...
}
//! [67]

//! [68]
function foo() {
    // Let bar() take care of this.
    print("calling bar() with " + arguments.length + "arguments");
    var result = return bar.apply(this, arguments);
    print("bar() returned" + result);
    return result;
}
//! [68]

//! [69]
QScriptValue foo(QScriptContext *ctx, QScriptEngine *eng)
{
    QScriptValue bar = eng->globalObject().property("bar");
    QScriptValue arguments = ctx->argumentsObject();
    qDebug() << "calling bar() with" << arguments.property("length").toInt32() << "arguments";
    QScriptValue result = bar.apply(ctx->thisObject(), arguments);
    qDebug() << "bar() returned" << result.toString();
    return result;
}
//! [69]

//! [70]
function counter() {
    var count = 0;
    return function() {
        return count++;
    }
}
//! [70]

//! [71]
var c1 = counter(); // create a new counter function
var c2 = counter(); // create a new counter function
print(c1()); // 0
print(c1()); // 1
print(c2()); // 0
print(c2()); // 1
//! [71]

//! [72]
QScriptValue counter(QScriptContext *ctx, QScriptEngine *eng)
{
    QScriptValue act = ctx->activationObject();
    act.setProperty("count", 0);
    QScriptValue result = eng->newFunction(counter_inner);
    result.setScope(act);
    return result;
}
//! [72]

//! [73]
QScriptValue counter_inner(QScriptContext *ctx, QScriptEngine *eng)
{
    QScriptValue outerAct = ctx->callee().scope();
    double count = outerAct.property("count").toNumber();
    outerAct.setProperty("count", count+1);
    return count;
}
//! [73]

//! [74]
QScriptValue counter_hybrid(QScriptContext *ctx, QScriptEngine *eng)
{
    QScriptValue act = ctx->activationObject();
    act.setProperty("count", 0);
    return eng->evaluate("function() { return count++; }");
}
//! [74]

//! [75]
function Book(isbn) {
    this.isbn = isbn;
}

var coolBook1 = new Book("978-0131872493");
var coolBook2 = new Book("978-1593271473");
//! [75]

//! [76]
QScriptValue Person_ctor(QScriptContext *ctx, QScriptEngine *eng)
{
    QScriptValue object;
    if (ctx->isCalledAsConstructor()) {
        object = ctx->thisObject();
    } else {
        object = eng->newObject();
        object.setPrototype(ctx->callee().property("prototype"));
    }
    object.setProperty("name", ctx->argument(0));
    return object;
}
//! [76]

//! [77]
QScriptContext *ctx = eng.pushContext();
QScriptValue act = ctx->activationObject();
act.setProperty("digit", 7);

qDebug() << eng.evaluate("digit + 1").toNumber(); // 8

eng.popContext();
//! [77]

//! [78]
QScriptValue getSet(QScriptContext *ctx, QScriptEngine *eng)
{
    QScriptValue obj = ctx->thisObject();
    QScriptValue data = obj.data();
    if (!data.isValid()) {
        data = eng->newObject();
        obj.setData(data);
    }
    QScriptValue result;
    if (ctx->argumentCount() == 1) {
        QString str = ctx->argument(0).toString();
        str.replace("Roberta", "Ken");
        result = str;
        data.setProperty("x", result);
    } else {
        result = data.property("x");
    }
    return result;
}
//! [78]

//! [79]
QScriptEngine eng;
QScriptValue obj = eng.newObject();
obj.setProperty("x", eng.newFunction(getSet),
                QScriptValue::PropertyGetter|QScriptValue::PropertySetter);
//! [79]

//! [80]
obj.x = "Roberta sent me";
print(obj.x); // "Ken sent me"
obj.x = "I sent the bill to Roberta";
print(obj.x); // "I sent the bill to Ken"
//! [80]

//! [81]
obj = {};
obj.__defineGetter__("x", function() { return this._x; });
obj.__defineSetter__("x", function(v) { print("setting x to", v); this._x = v; });
obj.x = 123;
//! [81]

//! [82]
myButton.text = qsTr("Hello world!");
//! [82]

//! [83]
myButton.text = qsTranslate("MyAwesomeScript", "Hello world!");
//! [83]

//! [84]
FriendlyConversation.prototype.greeting = function(type)
{
    if (FriendlyConversation['greeting_strings'] == undefined) {
        FriendlyConversation['greeting_strings'] = [
            QT_TR_NOOP("Hello"),
            QT_TR_NOOP("Goodbye")
        ];
    }
    return qsTr(FriendlyConversation.greeting_strings[type]);
}
//! [84]

//! [85]
FriendlyConversation.prototype.greeting = function(type)
{
    if (FriendlyConversation['greeting_strings'] == undefined) {
        FriendlyConversation['greeting_strings'] = [
            QT_TRANSLATE_NOOP("FriendlyConversation", "Hello"),
            QT_TRANSLATE_NOOP("FriendlyConversation", "Goodbye")
        ];
    }
    return qsTranslate("FriendlyConversation", FriendlyConversation.greeting_strings[type]);
}
//! [85]

//! [86]
FileCopier.prototype.showProgress = function(done, total, currentFileName)
{
    this.label.text = qsTr("%1 of %2 files copied.\nCopying: %3")
                      .arg(done)
                      .arg(total)
                      .arg(currentFileName));
}
//! [86]

//! [87]
lupdate myscript.qs -ts myscript_la.ts
//! [87]

//! [88]
lupdate -extensions qs scripts/ -ts scripts_la.ts
//! [88]

//! [89]
lrelease myscript_la.ts
//! [89]

//! [90]
({ unitName: "Celsius",
   toKelvin: function(x) { return x + 273; }
 })
//! [90]

//! [91]
QScriptValue object = engine.evaluate("({ unitName: 'Celsius', toKelvin: function(x) { return x + 273; } })");
QScriptValue toKelvin = object.property("toKelvin");
QScriptValue result = toKelvin.call(object, QScriptValueList() << 100);
qDebug() << result.toNumber(); // 373
//! [91]

//! [92]
QScriptValue add = engine.globalObject().property("add");
qDebug() << add.call(QScriptValue(), QScriptValueList() << 1 << 2).toNumber(); // 3
//! [92]

//! [93]
typedef QSharedPointer<QXmlStreamReader> XmlStreamReaderPointer;

Q_DECLARE_METATYPE(XmlStreamReaderPointer)

QScriptValue constructXmlStreamReader(QScriptContext *context, QScriptEngine *engine)
{
    if (!context->isCalledAsConstructor())
        return context->throwError(QScriptContext::SyntaxError, "please use the 'new' operator");

    QIODevice *device = qobject_cast<QIODevice*>(context->argument(0).toQObject());
    if (!device)
        return context->throwError(QScriptContext::TypeError, "please supply a QIODevice as first argument");

    // Create the C++ object
    QXmlStreamReader *reader = new QXmlStreamReader(device);

    XmlStreamReaderPointer pointer(reader);

    // store the shared pointer in the script object that we are constructing
    return engine->newVariant(context->thisObject(), qVariantFromValue(pointer));
}
//! [93]

//! [94]
QScriptValue xmlStreamReader_atEnd(QScriptContext *context, QScriptEngine *)
{
    XmlStreamReaderPointer reader = qscriptvalue_cast<XmlStreamReaderPointer>(context->thisObject());
    if (!reader)
        return context->throwError(QScriptContext::TypeError, "this object is not an XmlStreamReader");
    return reader->atEnd();
}
//! [94]

//! [95]
    QScriptEngine engine;
    QScriptValue xmlStreamReaderProto = engine.newObject();
    xmlStreamReaderProto.setProperty("atEnd", engine.newFunction(xmlStreamReader_atEnd));

    QScriptValue xmlStreamReaderCtor = engine.newFunction(constructXmlStreamReader, xmlStreamReaderProto);
    engine.globalObject().setProperty("XmlStreamReader", xmlStreamReaderCtor);
//! [95]