summaryrefslogtreecommitdiffstats
path: root/doc/src/scripting/qtscriptextensions.qdoc
diff options
context:
space:
mode:
Diffstat (limited to 'doc/src/scripting/qtscriptextensions.qdoc')
-rw-r--r--doc/src/scripting/qtscriptextensions.qdoc115
1 files changed, 115 insertions, 0 deletions
diff --git a/doc/src/scripting/qtscriptextensions.qdoc b/doc/src/scripting/qtscriptextensions.qdoc
new file mode 100644
index 0000000..d0317ff
--- /dev/null
+++ b/doc/src/scripting/qtscriptextensions.qdoc
@@ -0,0 +1,115 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at http://qt.nokia.com/contact.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+ \page qtscriptextensions.html
+ \title Creating QtScript Extensions
+ \brief A guide to creating and using QtScript extensions.
+
+ QtScript extensions can make additional functionality available to scripts
+ evaluated by a QScriptEngine. Extensions are imported by calling
+ the QScriptEngine::importExtension() function.
+
+ There are three ways to create an extension:
+
+ \list
+ \o Subclass QScriptExtensionPlugin and implement the desired functionality.
+ \o Implement the functionality in a script file.
+ \o Use a hybrid approach, where part of the functionality is implemented in a
+ QScriptExtensionPlugin, and part is implemented in a script file.
+ \endlist
+
+ The (dot-qualified) extension name is used to determine the path (relative to
+ the application's plugin path) where QScriptEngine will look for the script
+ file that will initialize the extension; if a file called \c{__init__.js}
+ (usually located in \c{[application plugin path]/script/foo/}) is
+ found in the corresponding folder, its contents will be evaluated by the engine
+ when the extension is imported.
+ As an example, if the extension is called \c{"foo.bar.baz"}, the engine will look
+ for \c{__init__.js} in \c{foo/bar/baz}. Additionally, before importing
+ \c{"foo.bar.baz"}, the engine will ensure that the extensions \c{"foo"} and \c{"foo.bar"}
+ are imported, locating and evaluating the corresponding \c{__init__.js}
+ in the same manner (in folders \c{foo} and \c{foo/bar}, respectively).
+
+ The contents of \c{__init__.js} are evaluated in a new QScriptContext,
+ as if it were the body of a function. The engine's Global Object acts as
+ the \c{this} object. The following local variables are initially available
+ to the script:
+
+ \list
+ \o \bold{__extension__}: The name of the extension (e.g. \c{"foo.bar.baz"}).
+ \o \bold{__setupPackage__}: A convenience function for setting up a "namespace" in the script environment. A typical application is to call \c{__setupPackage__()} with \c{__extension__} as argument; e.g. \c{__setupPackage__("foo.bar.baz")} would ensure that the object chain represented by the expression \c{foo.bar.baz} exists in the script environment. (This function is semantically equivalent to QScriptExtensionPlugin::setupPackage().)
+ \o \bold{__postInit__}: By default, this variable is undefined. If you assign a function to it, that function will be called \bold{after} the C++ plugin's initialize() function has been called. You can use this to perform further initialization that depends on e.g. native functions that the C++ plugin registers.
+ \endlist
+
+ An example of a simple \c{__init__.js}:
+
+ \snippet doc/src/snippets/code/doc_src_qtscriptextensions.qdoc 0
+
+ QScriptEngine will look for a QScriptExtensionPlugin that provides
+ the relevant extension by querying each plugin for its keys()
+ until a match is found. The plugin's initialize() function will be
+ called \bold{after} the relevant \c{__init__.js} (if any) has been
+ evaluated.
+
+ Continuining with the example of our imaginary extension \c{"foo.bar.baz"},
+ the following steps will be performed by QScriptEngine::importExtension():
+
+ \list
+ \o If it exists, \c{foo/__init__.js} is evaluated.
+ \o If a plugin with \c{"foo"} in its list of keys is found, its initialize() function is called with \c{"foo"} as key.
+ \o If it exists, \c{foo/bar/__init__.js} is evaluated.
+ \o If a plugin with \c{"foo.bar"} in its list of keys is found, its initialize() function is called with \c{"foo.bar"} as key.
+ \o If it exists, \c{foo/bar/baz/__init__.js} is evaluated.
+ \o If a plugin with "foo.bar.baz" in its list of keys is found, its initialize() function is called with \c{"foo.bar.baz"} as key.
+ \endlist
+
+ \section1 Static Extensions
+
+ When an extension is compiled and linked into your application as a
+ static plugin, Qt Script will look for the optional \c{__init__.js}
+ script in a resource, prefixed by \c{:/qtscriptextension}. For example,
+ if the extension key is "foo.bar", Qt Script will evaluate the contents
+ of the file \c{:/qtscriptextension/foo/bar/__init__.js}, if it
+ exists. Note that if the resource is built into the plugin, you may
+ need to use the Q_INIT_RESOURCE() macro to initialize the resource
+ before importing the extension.
+*/