QSInterpreter Class Reference

The QSInterpreter class provides the public API for the Qt Script for Applications script engine. More...

#include <qsinterpreter.h>

List of all member functions.

Public Members

Public Slots

Signals

Static Public Members

Properties


Detailed Description

The QSInterpreter class provides the public API for the Qt Script for Applications script engine.

This class (implemented in libqsa) provides the functionality required to make Qt/C++ applications scriptable with Qt Script.

For convenience reasons, a single instance of the QSInterpreter class exists in an application; it is available as QSInterpreter::defaultInterpreter().

The functions evaluate(), call(), addTransientObject(), and clear() provide the basic functionality of the interpreter. Any string containing valid Qt Script code can be executed using evaluate(), and any state built up during evaluation will be kept between calls. The function call() can be used to call script functions from C++. The function addTransientObject() will add an object to the interpreter for a time. Calling clear() will clear the state of the interpreter and remove all transient objects.

The function checkSyntax() provides syntax checking without having to execute the context of the code.

QSInterpreter provides several functions for script introspection. These functions are: classes(), functions(), and variables().

If an error occurs, e.g. during the execution of a script, the error() signal is emitted. The error behavior depends on the errorMode() which is set with setErrorMode(). When the interpreter stops execution because of an error, the hadError(), errorMessage(), and stackTrace() functions can be used to provide error information.

See the Manual for more explanations and examples.


Member Type Documentation

QSInterpreter::ClassFlags

The ClassFlags enum describes which method should be used for class introspection.

QSInterpreter::ErrorMode

The ErrorMode enum describes what happens when an error occurs while parsing or executing script code.

QSInterpreter::FunctionFlags

The FunctionFlags enum describes matching rules and formatting for function introspection.


Member Function Documentation

QSInterpreter::QSInterpreter ( QObject * parent = 0, const char * name = 0 )

Constructs a QSInterpreter that runs without a project.

The parent and name parameters are passed on to the QObject base class.

There's a default instance accessible with QSInterpreter::defaultInterpreter().

void QSInterpreter::addObjectFactory ( QSObjectFactory * factory )

Adds the object factory factory to the interpreter.

Using this function will clear the state of the interpreter.

void QSInterpreter::addTransientObject ( QObject * object )

Adds the object object to the interpreter.

Transient objects added to the interpreter are not persistent, meaning that when the interpreter is cleared, they are also removed. Also, when the project is re-evaluated the interpreter is cleared and these objects are removed.

Use QSProject::addObject() to add persistent objects to the interpreter.

See also QSProject::addObject().

void QSInterpreter::addTransientSignalHandler ( QObject * sender, const char * signal, const char * qtscriptFunction )

Adds the Qt Script function qtscriptFunction (fully qualified) as a transient signal handler for the C++ signal signal of the object sender.

Example:

  interpreter->addTransientSignalHandler( myButton, SIGNAL( clicked() ), "classA.obj.calculate" );
  

See also removeTransientSignalHandler().

void QSInterpreter::addWrapperFactory ( QSWrapperFactory * factory )

Adds the wrapper factory factory to the interpreter.

Using this function will clear the state of the interpreter.

QSArgument QSInterpreter::call ( const QString & function, const QSArgumentList & arguments = QSArgumentList ( ), QObject * context = 0 )

Calls the function function with the given arguments. The arguments are first converted into Qt Script datatypes.

Functions which were passed to evaluate() in previous calls or which are defined in the current project, can be called from this function.

If context is 0 (default), the function is called in the global scope. If a context is given, the function is called in the scope of that object.

Interpreters that belong to a project are subject to re-evaluation, since the code which has been passed previously into evaluate() gets lost when calling one of these functions. This happens when the project or the scripts in it are modified.

bool QSInterpreter::checkSyntax ( const QString & code )

Checks whether the script code code is free of syntax errors. Returns TRUE if the code is free of syntax errors; otherwise returns FALSE.

QStringList QSInterpreter::classes ( ClassFlags flags = AllClasses ) const

Returns the classes in the interpreter.

If flags is AllClasses (default), all classes in the interpreter are returned, including those declared in object contexts. If flags is GlobalClasses, only classes declared in the global context are returned.

See also functions() and variables().

QStringList QSInterpreter::classes ( const QString & context ) const

Returns all classes declared in the fully qualified context context.

See also functions() and variables().

QStringList QSInterpreter::classes ( QObject * context ) const

Returns all classes declared in the context context.

See also functions() and variables().

void QSInterpreter::clear () [slot]

Clears the state of the interpreter.

When the interpreter is cleared, all declarations parsed using the function QSInterpreter::evaluate() are removed. The state of all variables will also be cleared.

Clearing the interpreter will also remove the non-persistant objects. Non persistant objects are those added with the function QSInterpreter::addObject() or by evaluating code in the context of a QObject using QSInterpreter::evaluate();

This function does not clear persistent application objects added by the function QSProject::addObject().

QObject * QSInterpreter::currentContext () const

Returns the current execution context of the interpreter. This is either a QObject pointer or 0.

QSInterpreter * QSInterpreter::defaultInterpreter () [static]

Returns the default interpreter.

The default interpreter runs without a project.

This function will automatically create the interpreter if it doesn't already exist.

void QSInterpreter::error ( const QString & message, const QString & scriptName, int lineNumber ) [signal]

This signal is emitted if an error occurs when running or parsing a script. message contains the error message from the interpreter, scriptName contains the scriptname (if known) of where the error occurred, and lineNumber contains the line number at which the error occurred.

void QSInterpreter::error ( const QString & message, QObject * context, const QString & scriptName, int lineNumber ) [signal]

This signal is emitted if an error occurs when running or parsing a script. message contains the error message from the interpreter, context is a pointer to the QObject context in which the error occurred or 0, if the context is the global context, scriptName contains the scriptName (if known) of where the error occurred, and lineNumber contains the line number at which the error occurred.

QString QSInterpreter::errorMessage () const

Returns the error message that was last reported if there was an error; otherwise returns QString::null

ErrorMode QSInterpreter::errorMode () const

Returns what occurs when there is an error:. See the "errorMode" property for details.

QSArgument QSInterpreter::evaluate ( const QString & code, QObject * context = 0, const QString & scriptName = QString::null )

Executes the string of Qt Script in code and returns any value produced by that code.

This function executes the code passed in as code. The code can use and reference code (functions, classes, variables, etc.) which have been passed to this function previously or which are defined in the current project, if present. Also, application objects which have been added via addObject() can be accessed.

If context is 0 (default), the code is executed as global code. If a context is given, the code is executed in the context of that object.

Interpreters that belong to a project are subject to re-evaluation, since the code which has been passed previously into evaluate() gets lost when calling one of these functions. This happens when the project or the scripts in it are modified.

scriptName can be used for error reporting and debugging.

QStringList QSInterpreter::functions ( FunctionFlags flags = FunctionNames ) const

Returns all the functions in global context.

If flags does not include FunctionSignatures (default), only the function names are returned. If flags does include FunctionSignatures, then each function name returned will be on the following form:

  functionName( typeOfArg1, typeOfArg2, ... )
  

See also classes() and variables().

QStringList QSInterpreter::functions ( const QString & context, uint flags = FunctionNames ) const

Returns all script functions in the context context (this can be e.g. a class or form). If context is empty, the functions of the global context (global functions) are returned.

context can be fully qualified.

If flags does not include FunctionSignatures (default), only the function names are returned. If flags does include FunctionSignatures, then each function name returned will be on the following form:

  functionName( typeOfArg1, typeOfArg2, ... )
  

If flags includes IncludeMemberFunctions and context represents a class declared in script, this function will return all static and non static functions; otherwise only returns static functions.

See also classes() and variables().

QStringList QSInterpreter::functions ( QObject * context, FunctionFlags flags = FunctionNames ) const

Returns all script functions which have been defined in the context context.

If flags does not include FunctionSignatures (default), only the function names are returned. If flags does include FunctionSignatures, then each function name returned will be on the following form:

  functionName( typeOfArg1, typeOfArg2, ... )
  

See also classes() and variables().

bool QSInterpreter::hadError () const

Returns TRUE if the interpreter had an error during the last execution; otherwise returns FALSE.

bool QSInterpreter::isRunning () const

Return TRUE if the interpreter is currently evaluating code; otherwise returns FALSE.

QObjectList QSInterpreter::presentObjects () const

Returns the list of objects currently available for scripting in this interpreter.

QSProject * QSInterpreter::project () const

Returns the current project of the interpreter or 0 if there is no project.

void QSInterpreter::removeTransientSignalHandler ( QObject * sender, const char * signal, const char * qtscriptFunction )

Removes the connection between the signal signal of the object sender and the fully qualified signal handler qtscriptFunction.

See also addTransientSignalHandler().

void QSInterpreter::setErrorMode ( ErrorMode m )

Sets what occurs when there is an error: to m. See the "errorMode" property for details.

QSStackTrace QSInterpreter::stackTrace () const

Returns the stack trace describing the call stack of the last reported error if there was an error; otherwise returns an empty stack trace.

void QSInterpreter::throwError ( const QString & message )

Informs the interpreter that an error has occurred. The error is treated like a normal Qt Script error. The error message is passed in message.

QStringList QSInterpreter::variables () const

Returns all variables declared in the global context.

See also functions() and classes().

QStringList QSInterpreter::variables ( const QString & context ) const

Returns all variables declared in the fully qualified context context.

See also functions() and classes().

QStringList QSInterpreter::variables ( QObject * context ) const

Returns all variables declared in the contenxt context.

See also functions() and classes().


Property Documentation

ErrorMode errorMode

This property holds what occurs when there is an error:.

Set this property's value with setErrorMode() and get this property's value with errorMode().