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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
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****************************************************************************/
/*!
\example script/calculator
\title QtScript Calculator Example
\ingroup scripting
In this simple QtScript example, we show how to implement the
functionality of a calculator widget.
\image qtscript-calculator-example.png
The program logic in this example is a fairly straight port of the logic in the C++ \l{Calculator Example}.
The graphical user interface is defined in a UI file.
The C++ part of the example consists of four steps:
\list
\o Evaluate the script code that defines the \c{Calculator} class.
\snippet examples/script/calculator/main.cpp 0a
\snippet examples/script/calculator/main.cpp 0b
\o Create a widget from the UI file using QUiLoader.
\snippet examples/script/calculator/main.cpp 1
\o Call the Calculator constructor function to create a new \c{Calculator} script object, passing the widget as argument.
\snippet examples/script/calculator/main.cpp 2
\o Show the widget and start the application event loop.
\snippet examples/script/calculator/main.cpp 3
\endlist
On the script side, the \c{Calculator} constructor function
initializes the instance variables of the new \c{Calculator}
object, and connects the clicked() signal of the form's buttons
to corresponding functions defined in the \c{Calculator} prototype
object; the effect is that when a button is clicked, the proper
script function will be invoked to carry out the operation.
\snippet examples/script/calculator/calculator.js 0
A \c{Calculator} object is just a plain script object; it is not
a widget. Instead, it stores a reference to the calculator form
(the widget) in an instance variable, \c{ui}. The calculator
script functions can access components of the form by referring
to the proper children of the \c{ui} member.
\snippet examples/script/calculator/calculator.js 1
The digitClicked() function uses the special local variable
__qt_sender__ to access the object that triggered the signal;
this gives us a simple way to retrieve the value of the digit
that was clicked.
\snippet examples/script/calculator/calculator.js 2
The changeSign() function shows how we retrieve the text property
of the calculator's display, change it appropriately, and write
back the new value.
*/
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