source: trunk/doc/src/examples/qtscriptcustomclass.qdoc@ 651

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/*!
    \example script/customclass
    \title Custom Script Class Example

    The Custom Script Class example shows how to use QScriptClass and QScriptClassPropertyIterator
    to implement a custom script class.

    The script class we are going to implement is called \c{ByteArray}. It provides a wrapper around
    the QByteArray class in Qt, with a simplified API. Why do we need such a class? Well, neither the
    ECMAScript \c{Array} class or \c{String} class is appropriate to use when working with arrays of
    bytes. Our \c{ByteArray} class will have the right semantics; objects will use only the amount of
    memory that is really needed (a byte is stored as a byte, not as a floating-point number or a
    Unicode character) and can be passed directly to C++ slots taking QByteArray arguments (no costly
    conversion necessary).

    \section1 ByteArray Class In Use

    When the \c{ByteArray} class has been made available to the
    scripting environment, \c{ByteArray} objects can be constructed like
    so:

    \snippet doc/src/snippets/code/doc_src_examples_qtscriptcustomclass.qdoc 0

    \c{ByteArray} objects behave similar to normal \c{Array} objects. Every \c{ByteArray} object has
    a \c{length} property, that holds the length of the array. If a new value is assigned to the \c{length}
    property, the array is resized. If the array is enlarged, the new bytes are initialized to 0.
    (This is a difference from normal \c{Array} objects; \c{ByteArray} objects are always dense arrays.)
    Use normal array operations to read or write bytes in the array. The following code sets all the
    bytes of an array to a certain value:

    \snippet doc/src/snippets/code/doc_src_examples_qtscriptcustomclass.qdoc 1

    When assigning a value to an array element, the value is truncated to eight bits:

    \snippet doc/src/snippets/code/doc_src_examples_qtscriptcustomclass.qdoc 2

    Like normal \c{Array} objects, if the array index is greater than the current length
    of the array, the array is resized accordingly:

    \snippet doc/src/snippets/code/doc_src_examples_qtscriptcustomclass.qdoc 3

    Property names that aren't valid array indexes are treated
    like normal object properties (again, the same is the case for normal \c{Array} objects);
    in other words, it's perfectly fine to do something like this:

    \snippet doc/src/snippets/code/doc_src_examples_qtscriptcustomclass.qdoc 4

    The above assignment won't affect the contents of the array, but will rather assign a value
    to the object property named "foo".