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    41 

    42 /*!

    43     \example script/calculator

    44     \title QtScript Calculator Example

    45 

    46     In this simple QtScript example, we show how to implement the

    47     functionality of a calculator widget.

    48 

    49     \image qtscript-calculator-example.png

    50 

    51     The program logic in this example is a fairly straight port of the logic in the C++ \l{Calculator Example}.

    52     The graphical user interface is defined in a UI file.

    53 

    54     The C++ part of the example consists of four steps:

    55     \list

    56     \o Evaluate the script code that defines the \c{Calculator} class.

    57 

    58     \snippet examples/script/calculator/main.cpp 0a

    59     \snippet examples/script/calculator/main.cpp 0b

    60 

    61     \o Create a widget from the UI file using QUiLoader.

    62 

    63     \snippet examples/script/calculator/main.cpp 1

    64 

    65     \o Call the Calculator constructor function to create a new \c{Calculator} script object, passing the widget as argument.

    66 

    67     \snippet examples/script/calculator/main.cpp 2

    68 

    69     \o Show the widget and start the application event loop.

    70 

    71     \snippet examples/script/calculator/main.cpp 3

    72 

    73     \endlist

    74 

    75     On the script side, the \c{Calculator} constructor function

    76     initializes the instance variables of the new \c{Calculator}

    77     object, and connects the clicked() signal of the form's buttons

    78     to corresponding functions defined in the \c{Calculator} prototype

    79     object; the effect is that when a button is clicked, the proper

    80     script function will be invoked to carry out the operation.

    81 

    82     \snippet examples/script/calculator/calculator.js 0

    83 

    84     A \c{Calculator} object is just a plain script object; it is not

    85     a widget. Instead, it stores a reference to the calculator form

    86     (the widget) in an instance variable, \c{ui}. The calculator

    87     script functions can access components of the form by referring

    88     to the proper children of the \c{ui} member.

    89 

    90     \snippet examples/script/calculator/calculator.js 1

    91 

    92     The digitClicked() function is called when a digit button is

    93     clicked, with the input digit as argument.

    94 

    95     \snippet examples/script/calculator/calculator.js 2

    96 

    97     The changeSign() function shows how we retrieve the text property

    98     of the calculator's display, change it appropriately, and write

    99     back the new value.

   100 

   101 

   102 */