The QScriptEngine class provides an environment for evaluating Qt Script code. 更多...
| 头： | #include <QScriptEngine> |
| qmake: | QT += script |
| Since: | Qt 4.3 |
| 继承： | QObject |
注意： 此类的所有函数 可重入 .
| typedef | FunctionSignature |
| typedef | FunctionWithArgSignature |
| enum | QObjectWrapOption { ExcludeChildObjects, ExcludeSuperClassMethods, ExcludeSuperClassProperties, ExcludeSuperClassContents, ..., SkipMethodsInEnumeration } |
| flags | QObjectWrapOptions |
| enum | ValueOwnership { QtOwnership, ScriptOwnership, AutoOwnership } |
| QScriptEngine () | |
| QScriptEngine (QObject * parent ) | |
| virtual | ~QScriptEngine () |
| void | abortEvaluation (const QScriptValue & result = QScriptValue()) |
| QScriptEngineAgent * | agent () const |
| QStringList | availableExtensions () const |
| void | clearExceptions () |
| void | collectGarbage () |
| QScriptContext * | currentContext () const |
| QScriptValue | defaultPrototype (int metaTypeId ) const |
| QScriptValue | evaluate (const QString & program , const QString & fileName = QString(), int lineNumber = 1) |
| QScriptValue | evaluate (const QScriptProgram & program ) |
| T | fromScriptValue (const QScriptValue & value ) |
| QScriptValue | globalObject () const |
| bool | hasUncaughtException () const |
| QScriptValue | importExtension (const QString & extension ) |
| QStringList | importedExtensions () const |
| void | installTranslatorFunctions (const QScriptValue & object = QScriptValue()) |
| bool | isEvaluating () const |
| QScriptValue | newArray (uint length = 0) |
| QScriptValue | newDate (qsreal value ) |
| QScriptValue | newDate (const QDateTime & value ) |
| QScriptValue | newFunction (QScriptEngine::FunctionSignature fun , int length = 0) |
| QScriptValue | newFunction (QScriptEngine::FunctionSignature fun , const QScriptValue & prototype , int length = 0) |
| QScriptValue | newObject () |
| QScriptValue | newObject (QScriptClass * scriptClass , const QScriptValue & data = QScriptValue()) |
| QScriptValue | newQMetaObject (const QMetaObject * metaObject , const QScriptValue & ctor = QScriptValue()) |
| QScriptValue | newQObject (QObject * object , QScriptEngine::ValueOwnership ownership = QtOwnership, const QScriptEngine::QObjectWrapOptions & options = QObjectWrapOptions()) |
| QScriptValue | newQObject (const QScriptValue & scriptObject , QObject * qtObject , QScriptEngine::ValueOwnership ownership = QtOwnership, const QScriptEngine::QObjectWrapOptions & options = QObjectWrapOptions()) |
| QScriptValue | newRegExp (const QRegExp & regexp ) |
| QScriptValue | newRegExp (const QString & pattern , const QString & flags ) |
| QScriptValue | newVariant (const QVariant & value ) |
| QScriptValue | newVariant (const QScriptValue & object , const QVariant & value ) |
| QScriptValue | nullValue () |
| void | popContext () |
| int | processEventsInterval () const |
| QScriptContext * | pushContext () |
| void | reportAdditionalMemoryCost (int size ) |
| QScriptValue | scriptValueFromQMetaObject () |
| void | setAgent (QScriptEngineAgent * agent ) |
| void | setDefaultPrototype (int metaTypeId , const QScriptValue & prototype ) |
| void | setGlobalObject (const QScriptValue & object ) |
| void | setProcessEventsInterval (int interval ) |
| QScriptValue | toObject (const QScriptValue & value ) |
| QScriptValue | toScriptValue (const T & value ) |
| QScriptString | toStringHandle (const QString & str ) |
| QScriptValue | uncaughtException () const |
| QStringList | uncaughtExceptionBacktrace () const |
| int | uncaughtExceptionLineNumber () const |
| QScriptValue | undefinedValue () |
| void | signalHandlerException (const QScriptValue & exception ) |
| QScriptSyntaxCheckResult | checkSyntax (const QString & program ) |
| const QMetaObject | staticMetaObject |
| bool | qScriptConnect (QObject * sender , const char * signal , const QScriptValue & receiver , const QScriptValue & function ) |
| bool | qScriptDisconnect (QObject * sender , const char * signal , const QScriptValue & receiver , const QScriptValue & function ) |
| int | qScriptRegisterMetaType (QScriptEngine * eng , QScriptValue (*)(QScriptEngine *, const T &) toScriptValue , void (*)(const QScriptValue &, T &) fromScriptValue , const QScriptValue & prototype = QScriptValue(), T * = 0) |
| int | qScriptRegisterSequenceMetaType (QScriptEngine * engine , const QScriptValue & prototype = QScriptValue(), T * = 0) |
| QScriptValue | qScriptValueFromSequence (QScriptEngine * engine , const Container & container ) |
| void | qScriptValueToSequence (const QScriptValue & value , Container & container ) |
| Q_SCRIPT_DECLARE_QMETAOBJECT ( QMetaObject , ArgType ) |
The QScriptEngine class provides an environment for evaluating Qt Script code.
见 Qt Script documentation for information about the Qt Script language, and how to get started with scripting your C++ application.
使用
evaluate
() to evaluate script code; this is the C++ equivalent of the built-in script function
eval()
.
QScriptEngine myEngine; QScriptValue three = myEngine.evaluate("1 + 2");
evaluate () 返回 QScriptValue that holds the result of the evaluation. The QScriptValue class provides functions for converting the result to various C++ types (e.g. QScriptValue::toString () 和 QScriptValue::toNumber ()).
The following code snippet shows how a script function can be defined and then invoked from C++ using QScriptValue::call ():
QScriptValue fun = myEngine.evaluate("(function(a, b) { return a + b; })"); QScriptValueList args; args << 1 << 2; QScriptValue threeAgain = fun.call(QScriptValue(), args);
As can be seen from the above snippets, a script is provided to the engine in the form of a string. One common way of loading scripts is by reading the contents of a file and passing it to evaluate ():
QString fileName = "helloworld.qs"; QFile scriptFile(fileName); if (!scriptFile.open(QIODevice::ReadOnly)) // handle error QTextStream stream(&scriptFile); QString contents = stream.readAll(); scriptFile.close(); myEngine.evaluate(contents, fileName);
Here we pass the name of the file as the second argument to evaluate (). This does not affect evaluation in any way; the second argument is a general-purpose string that is used to identify the script for debugging purposes (for example, our filename will now show up in any uncaughtExceptionBacktrace () involving the script).
The globalObject () function returns the Global Object associated with the script engine. Properties of the Global Object are accessible from any script code (i.e. they are global variables). Typically, before evaluating "user" scripts, you will want to configure a script engine by adding one or more properties to the Global Object:
myEngine.globalObject().setProperty("myNumber", 123); ... QScriptValue myNumberPlusOne = myEngine.evaluate("myNumber + 1");
Adding custom properties to the scripting environment is one of the standard means of providing a scripting API that is specific to your application. Usually these custom properties are objects created by the newQObject () 或 newObject () functions, or constructor functions created by newFunction ().
evaluate
() can throw a script exception (e.g. due to a syntax error); in that case, the return value is the value that was thrown (typically an
Error
object). You can check whether the evaluation caused an exception by calling
hasUncaughtException
(). In that case, you can call toString() on the error object to obtain an error message. The current uncaught exception is also available through
uncaughtException
()。调用
clearExceptions
() will cause any uncaught exceptions to be cleared.
QScriptValue result = myEngine.evaluate(...); if (myEngine.hasUncaughtException()) { int line = myEngine.uncaughtExceptionLineNumber(); qDebug() << "uncaught exception at line" << line << ":" << result.toString(); }
The checkSyntax () function can be used to determine whether code can be usefully passed to evaluate ().
使用
newObject
() to create a standard Qt Script object; this is the C++ equivalent of the script statement
new Object()
. You can use the object-specific functionality in
QScriptValue
to manipulate the script object (e.g.
QScriptValue::setProperty
()). Similarly, use
newArray
() to create a Qt Script array object. Use
newDate
() 以创建
Date
object, and
newRegExp
() 以创建
RegExp
对象。
使用 newQObject () to wrap a QObject (or subclass) pointer. newQObject () returns a proxy script object; properties, children, and signals and slots of the QObject are available as properties of the proxy object. No binding code is needed because it is done dynamically using the Qt meta object system.
QPushButton button; QScriptValue scriptButton = myEngine.newQObject(&button); myEngine.globalObject().setProperty("button", scriptButton); myEngine.evaluate("button.checkable = true"); qDebug() << scriptButton.property("checkable").toBoolean(); scriptButton.property("show").call(); // call the show() slot
使用 qScriptConnect () to connect a C++ signal to a script function; this is the Qt Script equivalent of QObject::connect (). When a script function is invoked in response to a C++ signal, it can cause a script exception; you can connect to the signalHandlerException () signal to catch such an exception.
使用 newQMetaObject () to wrap a QMetaObject ; this gives you a "script representation" of a QObject -based class. newQMetaObject () returns a proxy script object; enum values of the class are available as properties of the proxy object. You can also specify a function that will be used to construct objects of the class (e.g. when the constructor is invoked from a script). For classes that have a "standard" Qt constructor, Qt Script can provide a default script constructor for you; see scriptValueFromQMetaObject ().
见 Making Applications Scriptable for more information on the QObject integration.
使用 newVariant () to wrap a QVariant . This can be used to store values of custom (non- QObject ) C++ types that have been registered with the Qt meta-type system. To make such types scriptable, you typically associate a prototype (delegate) object with the C++ type by calling setDefaultPrototype (); the prototype object defines the scripting API for the C++ type. Unlike the QObject integration, there is no automatic binding possible here; i.e. you have to create the scripting API yourself, for example by using the QScriptable 类。
使用 fromScriptValue () to cast from a QScriptValue to another type, and toScriptValue () 以创建 QScriptValue from another value. You can specify how the conversion of C++ types is to be performed with qScriptRegisterMetaType () 和 qScriptRegisterSequenceMetaType (). By default, Qt Script will use QVariant to store values of custom types.
使用 importExtension () to import plugin-based extensions into the engine. Call availableExtensions () to obtain a list naming all the available extensions, and importedExtensions () to obtain a list naming only those extensions that have been imported.
调用
pushContext
() to open up a new variable scope, and
popContext
() to close the current scope. This is useful if you are implementing an extension that evaluates script code containing temporary variable definitions (e.g.
var foo = 123;
) that are safe to discard when evaluation has completed.
使用 newFunction () to wrap native (C++) functions, including constructors for your own custom types, so that these can be invoked from script code. Such functions must have the signature QScriptEngine::FunctionSignature . You may then pass the function as argument to newFunction (). Here is an example of a function that returns the sum of its first two arguments:
QScriptValue myAdd(QScriptContext *context, QScriptEngine *engine) { QScriptValue a = context->argument(0); QScriptValue b = context->argument(1); return a.toNumber() + b.toNumber(); }
To expose this function to script code, you can set it as a property of the Global Object:
QScriptValue fun = myEngine.newFunction(myAdd); myEngine.globalObject().setProperty("myAdd", fun);
Once this is done, script code can call your function in the exact same manner as a "normal" script function:
QScriptValue result = myEngine.evaluate("myAdd(myNumber, 1)");
If you need to evaluate possibly long-running scripts from the main (GUI) thread, you should first call setProcessEventsInterval () to make sure that the GUI stays responsive. You can abort a currently running script by calling abortEvaluation (). You can determine whether an engine is currently running a script by calling isEvaluating ().
Qt Script objects may be garbage collected when they are no longer referenced. There is no guarantee as to when automatic garbage collection will take place.
The collectGarbage () function can be called to explicitly request garbage collection.
The reportAdditionalMemoryCost () function can be called to indicate that a Qt Script object occupies memory that isn't managed by the scripting environment. Reporting the additional cost makes it more likely that the garbage collector will be triggered. This can be useful, for example, when many custom, native Qt Script objects are allocated.
Since Qt 4.4, you can be notified of events pertaining to script execution (e.g. script function calls and statement execution) through the QScriptEngineAgent interface; see the setAgent () function. This can be used to implement debugging and profiling of a QScriptEngine .
另请参阅 QScriptValue , QScriptContext ，和 QScriptEngineAgent .
The function signature
QScriptValue f(QScriptContext *, QScriptEngine *)
.
A function with such a signature can be passed to QScriptEngine::newFunction () to wrap the function.
The function signature
QScriptValue f(QScriptContext *, QScriptEngine *, void *)
.
A function with such a signature can be passed to QScriptEngine::newFunction () to wrap the function.
These flags specify options when wrapping a QObject pointer with newQObject ().
| 常量 | 值 | 描述 |
|---|---|---|
QScriptEngine::ExcludeChildObjects
|
0x0001
|
The script object will not expose child objects as properties. |
QScriptEngine::ExcludeSuperClassMethods
|
0x0002
|
The script object will not expose signals and slots inherited from the superclass. |
QScriptEngine::ExcludeSuperClassProperties
|
0x0004
|
The script object will not expose properties inherited from the superclass. |
QScriptEngine::ExcludeSuperClassContents
|
0x0006
|
Shorthand form for ExcludeSuperClassMethods | ExcludeSuperClassProperties |
QScriptEngine::ExcludeDeleteLater
|
0x0010
|
The script object will not expose the QObject::deleteLater () 槽。 |
QScriptEngine::ExcludeSlots
|
0x0020
|
The script object will not expose the QObject 's slots. |
QScriptEngine::AutoCreateDynamicProperties
|
0x0100
|
Properties that don't already exist in the QObject will be created as dynamic properties of that object, rather than as properties of the script object. |
QScriptEngine::PreferExistingWrapperObject
|
0x0200
|
If a wrapper object with the requested configuration already exists, return that object. |
QScriptEngine::SkipMethodsInEnumeration
|
0x0008
|
Don't include methods (signals and slots) when enumerating the object's properties. |
The QObjectWrapOptions type is a typedef for QFlags <QObjectWrapOption>. It stores an OR combination of QObjectWrapOption values.
This enum specifies the ownership when wrapping a C++ value, e.g. by using newQObject ().
| 常量 | 值 | 描述 |
|---|---|---|
QScriptEngine::QtOwnership
|
0
|
The standard Qt ownership rules apply, i.e. the associated object will never be explicitly deleted by the script engine. This is the default. ( QObject ownership is explained in 对象树 & 所有权 )。 |
QScriptEngine::ScriptOwnership
|
1
|
The value is owned by the script environment. The associated data will be deleted when appropriate (i.e. after the garbage collector has discovered that there are no more live references to the value). |
QScriptEngine::AutoOwnership
|
2
|
If the associated object has a parent, the Qt ownership rules apply (QtOwnership); otherwise, the object is owned by the script environment (ScriptOwnership). |
构造 QScriptEngine 对象。
The globalObject () is initialized to have properties as described in ECMA-262 , Section 15.1.
构造 QScriptEngine 对象采用给定 parent .
The globalObject () is initialized to have properties as described in ECMA-262 , Section 15.1.
[虚拟]
QScriptEngine::
~QScriptEngine
()
销毁此 QScriptEngine .
Aborts any script evaluation currently taking place in this engine. The given result is passed back as the result of the evaluation (i.e. it is returned from the call to evaluate () being aborted).
If the engine isn't evaluating a script (i.e. isEvaluating () returns false), this function does nothing.
Call this function if you need to abort a running script for some reason, e.g. when you have detected that the script has been running for several seconds without completing.
该函数在 Qt 4.4 引入。
另请参阅 evaluate (), isEvaluating ()，和 setProcessEventsInterval ().
Returns the agent currently installed on this engine, or 0 if no agent is installed.
该函数在 Qt 4.4 引入。
另请参阅 setAgent ().
Returns a list naming the available extensions that can be imported using the importExtension () function. This list includes extensions that have been imported.
该函数在 Qt 4.4 引入。
另请参阅 importExtension () 和 importedExtensions ().
[static]
QScriptSyntaxCheckResult
QScriptEngine::
checkSyntax
(const
QString
&
program
)
Checks the syntax of the given program 。返回 QScriptSyntaxCheckResult object that contains the result of the check.
该函数在 Qt 4.5 引入。
Clears any uncaught exceptions in this engine.
该函数在 Qt 4.4 引入。
另请参阅 hasUncaughtException ().
Runs the garbage collector.
The garbage collector will attempt to reclaim memory by locating and disposing of objects that are no longer reachable in the script environment.
Normally you don't need to call this function; the garbage collector will automatically be invoked when the QScriptEngine decides that it's wise to do so (i.e. when a certain number of new objects have been created). However, you can call this function to explicitly request that garbage collection should be performed as soon as possible.
另请参阅 reportAdditionalMemoryCost ().
Returns the current context.
The current context is typically accessed to retrieve the arguments and `this' object in native functions; for convenience, it is available as the first argument in QScriptEngine::FunctionSignature .
Returns the default prototype associated with the given metaTypeId ，或无效 QScriptValue if no default prototype has been set.
另请参阅 setDefaultPrototype ().
Evaluates program ，使用 lineNumber as the base line number, and returns the result of the evaluation.
The script code will be evaluated in the current context.
The evaluation of
program
can cause an exception in the engine; in this case the return value will be the exception that was thrown (typically an
Error
object). You can call
hasUncaughtException
() to determine if an exception occurred in the last call to evaluate().
lineNumber is used to specify a starting line number for program ; line number information reported by the engine that pertain to this evaluation (e.g. uncaughtExceptionLineNumber ()) will be based on this argument. For example, if program consists of two lines of code, and the statement on the second line causes a script exception, uncaughtExceptionLineNumber () would return the given lineNumber plus one. When no starting line number is specified, line numbers will be 1-based.
fileName is used for error reporting. For example in error objects the file name is accessible through the "fileName" property if it's provided with this function.
另请参阅 canEvaluate (), hasUncaughtException (), isEvaluating ()，和 abortEvaluation ().
Evaluates the given program and returns the result of the evaluation.
该函数在 Qt 4.7 引入。
返回给定
value
被转换成模板类型
T
.
注意，
T
must be known to
QMetaType
.
见 Conversion Between Qt Script and C++ Types for a description of the built-in type conversion provided by Qt Script.
另请参阅 toScriptValue () 和 qScriptRegisterMetaType ().
Returns this engine's Global Object.
By default, the Global Object contains the built-in objects that are part of ECMA-262 , such as Math, Date and String. Additionally, you can set properties of the Global Object to make your own extensions available to all script code. Non-local variables in script code will be created as properties of the Global Object, as well as local variables in global code.
另请参阅 setGlobalObject ().
Returns true if the last script evaluation resulted in an uncaught exception; otherwise returns false.
The exception state is cleared when evaluate () 被调用。
另请参阅 uncaughtException () 和 uncaughtExceptionLineNumber ().
Imports the given
extension
到此
QScriptEngine
。返回
undefinedValue
() if the extension was successfully imported. You can call
hasUncaughtException
() to check if an error occurred; in that case, the return value is the value that was thrown by the exception (usually an
Error
对象)。
QScriptEngine ensures that a particular extension is only imported once; subsequent calls to importExtension() with the same extension name will do nothing and return undefinedValue ().
另请参阅 availableExtensions (), QScriptExtensionPlugin ，和 Creating Qt Script Extensions .
Returns a list naming the extensions that have been imported using the importExtension () 函数。
该函数在 Qt 4.4 引入。
另请参阅 availableExtensions ().
Installs translator functions on the given object , or on the Global Object if no object is specified.
The relation between Qt Script translator functions and C++ translator functions is described in the following table:
| Script Function | Corresponding C++ Function |
|---|---|
| qsTr() | QObject::tr () |
| QT_TR_NOOP () | QT_TR_NOOP () |
| qsTranslate() | QCoreApplication::translate() |
| QT_TRANSLATE_NOOP () | QT_TRANSLATE_NOOP () |
| qsTrId() (since 4.7) | qtTrId () |
| QT_TRID_NOOP () (since 4.7) | QT_TRID_NOOP () |
该函数在 Qt 4.5 引入。
另请参阅 Qt 国际化 .
Returns true if this engine is currently evaluating a script, otherwise returns false.
该函数在 Qt 4.4 引入。
另请参阅 evaluate () 和 abortEvaluation ().
Creates a Qt Script object of class Array with the given length .
另请参阅 newObject ().
Creates a Qt Script object of class Date with the given value (the number of milliseconds since 01 January 1970, UTC).
Creates a Qt Script object of class Date from the given value .
另请参阅 QScriptValue::toDateTime ().
创建
QScriptValue
that wraps a native (C++) function.
fun
must be a C++ function with signature
QScriptEngine::FunctionSignature
.
length
is the number of arguments that
fun
expects; this becomes the
length
property of the created
QScriptValue
.
注意， length only gives an indication of the number of arguments that the function expects; an actual invocation of a function can include any number of arguments. You can check the argumentCount() 的 QScriptContext associated with the invocation to determine the actual number of arguments passed.
A
prototype
property is automatically created for the resulting function object, to provide for the possibility that the function will be used as a constructor.
By combining newFunction() and the property flags QScriptValue::PropertyGetter and QScriptValue::PropertySetter , you can create script object properties that behave like normal properties in script code, but are in fact accessed through functions (analogous to how properties work in Qt 的特性系统 ). Example:
static QScriptValue getSetFoo(QScriptContext *context, QScriptEngine *engine) { QScriptValue callee = context->callee(); if (context->argumentCount() == 1) // writing? callee.setProperty("value", context->argument(0)); return callee.property("value"); } .... QScriptValue object = engine.newObject(); object.setProperty("foo", engine.newFunction(getSetFoo), QScriptValue::PropertyGetter | QScriptValue::PropertySetter);
When the property
foo
of the script object is subsequently accessed in script code,
getSetFoo()
will be invoked to handle the access. In this particular case, we chose to store the "real" value of
foo
as a property of the accessor function itself; you are of course free to do whatever you like in this function.
In the above example, a single native function was used to handle both reads and writes to the property; the argument count is used to determine if we are handling a read or write. You can also use two separate functions; just specify the relevant flag ( QScriptValue::PropertyGetter or QScriptValue::PropertySetter ) when setting the property, e.g.:
QScriptValue object = engine.newObject(); object.setProperty("foo", engine.newFunction(getFoo), QScriptValue::PropertyGetter); object.setProperty("foo", engine.newFunction(setFoo), QScriptValue::PropertySetter);
另请参阅 QScriptValue::call ().
Creates a constructor function from
fun
，采用给定
length
。
prototype
property of the resulting function is set to be the given
prototype
。
构造函数
property of
prototype
is set to be the resulting function.
When a function is called as a constructor (e.g.
new Foo()
), the `this' object associated with the function call is the new object that the function is expected to initialize; the prototype of this default constructed object will be the function's public
prototype
property. If you always want the function to behave as a constructor (e.g.
Foo()
should also create a new object), or if you need to create your own object rather than using the default `this' object, you should make sure that the prototype of your object is set correctly; either by setting it manually, or, when wrapping a custom type, by having registered the
defaultPrototype
() of that type. Example:
QScriptValue Foo(QScriptContext *context, QScriptEngine *engine) { if (context->calledAsConstructor()) { // initialize the new object context->thisObject().setProperty("bar", ...); // ... // return a non-object value to indicate that the // thisObject() should be the result of the "new Foo()" expression return engine->undefinedValue(); } else { // not called as "new Foo()", just "Foo()" // create our own object and return that one QScriptValue object = engine->newObject(); object.setPrototype(context->callee().property("prototype")); object.setProperty("baz", ...); return object; } } ... QScriptValue fooProto = engine->newObject(); fooProto.setProperty("whatever", ...); engine->globalObject().setProperty("Foo", engine->newFunction(Foo, fooProto));
To wrap a custom type and provide a constructor for it, you'd typically do something like this:
class Bar { ... }; Q_DECLARE_METATYPE(Bar) QScriptValue constructBar(QScriptContext *context, QScriptEngine *engine) { Bar bar; // initialize from arguments in context, if desired ... return engine->toScriptValue(bar); } class BarPrototype : public QObject, public QScriptable { // provide the scriptable interface of this type using slots and properties ... }; ... // create and register the Bar prototype and constructor in the engine BarPrototype *barPrototypeObject = new BarPrototype(...); QScriptValue barProto = engine->newQObject(barPrototypeObject); engine->setDefaultPrototype(qMetaTypeId<Bar>, barProto); QScriptValue barCtor = engine->newFunction(constructBar, barProto); engine->globalObject().setProperty("Bar", barCtor);
Creates a Qt Script object of class Object.
The prototype of the created object will be the Object prototype object.
另请参阅 newArray () 和 QScriptValue::setProperty ().
这是重载函数。
Creates a Qt Script Object of the given class, scriptClass .
The prototype of the created object will be the Object prototype object.
data , if specified, is set as the internal data of the new object (using QScriptValue::setData ()).
该函数在 Qt 4.4 引入。
另请参阅 QScriptValue::scriptClass () 和 reportAdditionalMemoryCost ().
Creates a Qt Script object that represents a QObject class, using the the given metaObject and constructor ctor .
Enums of metaObject (declared with Q_ENUMS) are available as properties of the created QScriptValue . When the class is called as a function, ctor will be called to create a new instance of the class.
范例：
QScriptValue mySpecialQObjectConstructor(QScriptContext *context, QScriptEngine *engine) { QObject *parent = context->argument(0).toQObject(); QObject *object = new QObject(parent); return engine->newQObject(object, QScriptEngine::ScriptOwnership); } ... QScriptValue ctor = engine.newFunction(mySpecialQObjectConstructor); QScriptValue metaObject = engine.newQMetaObject(&QObject::staticMetaObject, ctor); engine.globalObject().setProperty("QObject", metaObject); QScriptValue result = engine.evaluate("new QObject()");
另请参阅 newQObject () 和 scriptValueFromQMetaObject ().
Creates a Qt Script object that wraps the given QObject object ，使用给定 ownership . The given options control various aspects of the interaction with the resulting script object.
Signals and slots, properties and children of object are available as properties of the created QScriptValue . For more information, see the Qt Script 文档编制。
若 object is a null pointer, this function returns nullValue ().
If a default prototype has been registered for the object 's class (or its superclass, recursively), the prototype of the new script object will be set to be that default prototype.
若给定 object is deleted outside of Qt Script's control, any attempt to access the deleted QObject 's members through the Qt Script wrapper object (either by script code or C++) will result in a script exception.
另请参阅 QScriptValue::toQObject () 和 reportAdditionalMemoryCost ().
这是重载函数。
Initializes the given scriptObject to hold the given qtObject , and returns the scriptObject .
This function enables you to "promote" a plain Qt Script object (created by the newObject () function) to a QObject proxy, or to replace the QObject contained inside an object previously created by the newQObject () 函数。
The prototype() of the scriptObject will remain unchanged.
若 scriptObject is not an object, this function behaves like the normal newQObject (), i.e. it creates a new script object and returns it.
This function is useful when you want to provide a script constructor for a
QObject
-based class. If your constructor is invoked in a
new
expression (
QScriptContext::isCalledAsConstructor
() returns true), you can pass
QScriptContext::thisObject
() (the default constructed script object) to this function to initialize the new object.
该函数在 Qt 4.4 引入。
另请参阅 reportAdditionalMemoryCost ().
Creates a Qt Script object of class RegExp with the given regexp .
另请参阅 QScriptValue::toRegExp ().
Creates a Qt Script object of class RegExp with the given pattern and flags .
The legal flags are 'g' (global), 'i' (ignore case), and 'm' (multiline).
Creates a Qt Script object holding the given variant value .
If a default prototype has been registered with the meta type id of value , then the prototype of the created object will be that prototype; otherwise, the prototype will be the Object prototype object.
另请参阅 setDefaultPrototype (), QScriptValue::toVariant ()，和 reportAdditionalMemoryCost ().
这是重载函数。
Initializes the given Qt Script object to hold the given variant value , and returns the object .
This function enables you to "promote" a plain Qt Script object (created by the newObject () function) to a variant, or to replace the variant contained inside an object previously created by the newVariant () 函数。
The prototype() of the object will remain unchanged.
若 object is not an object, this function behaves like the normal newVariant (), i.e. it creates a new script object and returns it.
This function is useful when you want to provide a script constructor for a C++ type. If your constructor is invoked in a
new
expression (
QScriptContext::isCalledAsConstructor
() returns true), you can pass
QScriptContext::thisObject
() (the default constructed script object) to this function to initialize the new object.
该函数在 Qt 4.4 引入。
另请参阅 reportAdditionalMemoryCost ().
返回 QScriptValue of the primitive type Null.
另请参阅 undefinedValue ().
Pops the current execution context and restores the previous one. This function must be used in conjunction with pushContext ().
另请参阅 pushContext ().
Returns the interval in milliseconds between calls to QCoreApplication::processEvents () while the interpreter is running.
另请参阅 setProcessEventsInterval ().
Enters a new execution context and returns the associated QScriptContext 对象。
Once you are done with the context, you should call popContext () to restore the old context.
By default, the `this' object of the new context is the Global Object. The context's callee () will be invalid.
This function is useful when you want to evaluate script code as if it were the body of a function. You can use the context's activationObject () to initialize local variables that will be available to scripts. Example:
QScriptEngine engine; QScriptContext *context = engine.pushContext(); context->activationObject().setProperty("myArg", 123); engine.evaluate("var tmp = myArg + 42"); ... engine.popContext();
In the above example, the new variable "tmp" defined in the script will be local to the context; in other words, the script doesn't have any effect on the global environment.
Returns 0 in case of stack overflow
另请参阅 popContext ().
Reports an additional memory cost of the given size , measured in bytes, to the garbage collector.
This function can be called to indicate that a Qt Script object has memory associated with it that isn't managed by Qt Script itself. Reporting the additional cost makes it more likely that the garbage collector will be triggered.
Note that if the additional memory is shared with objects outside the scripting environment, the cost should not be reported, since collecting the Qt Script object would not cause the memory to be freed anyway.
Negative size values are ignored, i.e. this function can't be used to report that the additional memory has been deallocated.
该函数在 Qt 4.7 引入。
另请参阅 collectGarbage ().
创建
QScriptValue
that represents the Qt class
T
.
This function is used in combination with one of the Q_SCRIPT_DECLARE_QMETAOBJECT () macro. Example:
Q_SCRIPT_DECLARE_QMETAOBJECT(QLineEdit, QWidget*) ... QScriptValue lineEditClass = engine.scriptValueFromQMetaObject<QLineEdit>(); engine.globalObject().setProperty("QLineEdit", lineEditClass);
另请参阅 QScriptEngine::newQMetaObject ().
Installs the given agent on this engine. The agent will be notified of various events pertaining to script execution. This is useful when you want to find out exactly what the engine is doing, e.g. when evaluate () is called. The agent interface is the basis of tools like debuggers and profilers.
The engine maintains ownership of the agent .
Calling this function will replace the existing agent, if any.
该函数在 Qt 4.4 引入。
另请参阅 agent ().
Sets the default prototype of the C++ type identified by the given metaTypeId to prototype .
The default prototype provides a script interface for values of type metaTypeId when a value of that type is accessed from script code. Whenever the script engine (implicitly or explicitly) creates a QScriptValue from a value of type metaTypeId , the default prototype will be set as the QScriptValue 's prototype.
The prototype object itself may be constructed using one of two principal techniques; the simplest is to subclass QScriptable , which enables you to define the scripting API of the type through QObject properties and slots. Another possibility is to create a script object by calling newObject (), and populate the object with the desired properties (e.g. native functions wrapped with newFunction ()).
另请参阅 defaultPrototype (), qScriptRegisterMetaType (), QScriptable ，和 Default Prototypes Example .
Sets this engine's Global Object to be the given object 。若 object is not a valid script object, this function does nothing.
When setting a custom global object, you may want to use QScriptValueIterator to copy the properties of the standard Global Object; alternatively, you can set the internal prototype of your custom object to be the original Global Object.
该函数在 Qt 4.5 引入。
另请参阅 globalObject ().
Sets the interval between calls to QCoreApplication::processEvents to interval 毫秒。
While the interpreter is running, all event processing is by default blocked. This means for instance that the gui will not be updated and timers will not be fired. To allow event processing during interpreter execution one can specify the processing interval to be a positive value, indicating the number of milliseconds between each time QCoreApplication::processEvents () 被调用。
The default value is -1, which disables event processing during interpreter execution.
可以使用 QCoreApplication::postEvent () to post an event that performs custom processing at the next interval. For example, you could keep track of the total running time of the script and call abortEvaluation () when you detect that the script has been running for a long time without completing.
另请参阅 processEventsInterval ().
[signal]
void
QScriptEngine::
signalHandlerException
(const
QScriptValue
&
exception
)
This signal is emitted when a script function connected to a signal causes an exception .
该函数在 Qt 4.4 引入。
另请参阅 qScriptConnect ().
转换给定 value to an object, if such a conversion is possible; otherwise returns an invalid QScriptValue . The conversion is performed according to the following table:
| Input Type | 结果 |
|---|---|
| Undefined | An invalid QScriptValue . |
| Null | An invalid QScriptValue . |
| 布尔 | A new Boolean object whose internal value is set to the value of the boolean. |
| Number | A new Number object whose internal value is set to the value of the number. |
| 字符串 | A new String object whose internal value is set to the value of the string. |
| 对象 | The result is the object itself (no conversion). |
该函数在 Qt 4.5 引入。
另请参阅 newObject ().
创建 QScriptValue 采用给定 value .
Note that the template type
T
must be known to
QMetaType
.
见 Conversion Between Qt Script and C++ Types for a description of the built-in type conversion provided by Qt Script. By default, the types that are not specially handled by Qt Script are represented as QVariants (e.g. the value 会被传递给 newVariant ()); you can change this behavior by installing your own type conversion functions with qScriptRegisterMetaType ().
另请参阅 fromScriptValue () 和 qScriptRegisterMetaType ().
Returns a handle that represents the given string, str .
QScriptString can be used to quickly look up properties, and compare property names, of script objects.
该函数在 Qt 4.4 引入。
另请参阅 QScriptValue::property ().
Returns the current uncaught exception, or an invalid QScriptValue if there is no uncaught exception.
The exception value is typically an
Error
object; in that case, you can call toString() on the return value to obtain an error message.
另请参阅 hasUncaughtException () 和 uncaughtExceptionLineNumber ().
Returns a human-readable backtrace of the last uncaught exception.
It is in the form
<function-name>() at <file-name>:<line-number>
.
另请参阅 uncaughtException ().
Returns the line number where the last uncaught exception occurred.
Line numbers are 1-based, unless a different base was specified as the second argument to evaluate ().
另请参阅 hasUncaughtException ().
返回 QScriptValue of the primitive type Undefined.
另请参阅 nullValue ().
创建连接从 signal 在 sender 到给定 function 。若 receiver is an object, it will act as the `this' object when the signal handler function is invoked. Returns true if the connection succeeds; otherwise returns false.
该函数在 Qt 4.4 引入。
另请参阅 qScriptDisconnect () 和 QScriptEngine::signalHandlerException ().
断开连接 signal 在 sender from the given ( receiver , function ) pair. Returns true if the connection is successfully broken; otherwise returns false.
该函数在 Qt 4.4 引入。
另请参阅 qScriptConnect ().
Registers the type
T
以给定
eng
.
toScriptValue
must be a function that will convert from a value of type
T
到
QScriptValue
，和
fromScriptValue
a function that does the opposite.
prototype
, if valid, is the prototype that's set on QScriptValues returned by
toScriptValue
.
Returns the internal ID used by QMetaType .
You only need to call this function if you want to provide custom conversion of values of type
T
, i.e. if the default
QVariant
-based representation and conversion is not appropriate. (Note that custom
QObject
-derived types also fall in this category; e.g. for a
QObject
-derived class called MyObject, you probably want to define conversion functions for MyObject* that utilize
QScriptEngine::newQObject
() 和
QScriptValue::toQObject
().)
If you only want to define a common script interface for values of type
T
, and don't care how those values are represented (i.e. storing them in QVariants is fine), use
setDefaultPrototype
() instead; this will minimize conversion costs.
You need to declare the custom type first with Q_DECLARE_METATYPE ().
After a type has been registered, you can convert from a QScriptValue to that type using fromScriptValue (), and create a QScriptValue from a value of that type using toScriptValue (). The engine will take care of calling the proper conversion function when calling C++ slots, and when getting or setting a C++ property; i.e. the custom type may be used seamlessly on both the C++ side and the script side.
The following is an example of how to use this function. We will specify custom conversion of our type
MyStruct
. Here's the C++ type:
struct MyStruct { int x; int y; };
We must declare it so that the type will be known to QMetaType :
Q_DECLARE_METATYPE(MyStruct)
Next, the
MyStruct
conversion functions. We represent the
MyStruct
value as a script object and just copy the properties:
QScriptValue toScriptValue(QScriptEngine *engine, const MyStruct &s) { QScriptValue obj = engine->newObject(); obj.setProperty("x", s.x); obj.setProperty("y", s.y); return obj; } void fromScriptValue(const QScriptValue &obj, MyStruct &s) { s.x = obj.property("x").toInt32(); s.y = obj.property("y").toInt32(); }
Now we can register
MyStruct
with the engine:
qScriptRegisterMetaType(engine, toScriptValue, fromScriptValue);
Working with
MyStruct
values is now easy:
MyStruct s = qscriptvalue_cast<MyStruct>(context->argument(0)); ... MyStruct s2; s2.x = s.x + 10; s2.y = s.y + 20; QScriptValue v = engine->toScriptValue(s2);
If you want to be able to construct values of your custom type from script code, you have to register a constructor function for the type. For example:
QScriptValue createMyStruct(QScriptContext *, QScriptEngine *engine) { MyStruct s; s.x = 123; s.y = 456; return engine->toScriptValue(s); } ... QScriptValue ctor = engine.newFunction(createMyStruct); engine.globalObject().setProperty("MyStruct", ctor);
另请参阅 qScriptRegisterSequenceMetaType () 和 qRegisterMetaType ().
Registers the sequence type
T
以给定
engine
. This function provides conversion functions that convert between
T
and Qt Script
数组
对象。
T
must provide a const_iterator class and begin(), end() and push_back() functions. If
prototype
is valid, it will be set as the prototype of
数组
objects due to conversion from
T
; otherwise, the standard
数组
prototype will be used.
Returns the internal ID used by QMetaType .
You need to declare the container type first with Q_DECLARE_METATYPE (). If the element type isn't a standard Qt/C++ type, it must be declared using Q_DECLARE_METATYPE () as well. Example:
Q_DECLARE_METATYPE(QVector<int>) ... qScriptRegisterSequenceMetaType<QVector<int> >(engine); ... QVector<int> v = qscriptvalue_cast<QVector<int> >(engine->evaluate("[5, 1, 3, 2]")); qSort(v.begin(), v.end()); QScriptValue a = engine->toScriptValue(v); qDebug() << a.toString(); // outputs "[1, 2, 3, 5]"
另请参阅 qScriptRegisterMetaType ().
Creates an array in the form of a
QScriptValue
使用给定
engine
采用给定
container
of template type
容器
.
The
容器
type must provide a
const_iterator
class to enable the contents of the container to be copied into the array.
Additionally, the type of each element in the sequence should be suitable for conversion to a QScriptValue 。见 Conversion Between Qt Script and C++ Types for more information about the restrictions on types that can be used with QScriptValue .
该函数在 Qt 4.3 引入。
另请参阅 QScriptEngine::fromScriptValue ().
Copies the elements in the sequence specified by
value
到给定
container
of template type
容器
.
The
value
used is typically an array, but any container can be copied as long as it provides a
length
property describing how many elements it contains.
Additionally, the type of each element in the sequence must be suitable for conversion to a C++ type from a QScriptValue 。见 Conversion Between Qt Script and C++ Types for more information about the restrictions on types that can be used with QScriptValue .
该函数在 Qt 4.3 引入。
另请参阅 qscriptvalue_cast ().
Declares the given
QMetaObject
. Used in combination with
QScriptEngine::scriptValueFromQMetaObject
() to make enums and instantiation of
QMetaObject
available to script code. The constructor generated by this macro takes a single argument of type
ArgType
; typically the argument is the parent type of the new instance, in which case
ArgType
is
QWidget*
or
QObject*
. Objects created by the constructor will have
QScriptEngine::AutoOwnership
ownership.
该函数在 Qt 4.3 引入。