Recipes Example

The UI for this example was created using https://:

The UI consists of three https:// arranged vertically. The top one contains a https:// that displays the XML text from the cookbook file. The middle group box contains a https:// for choosing the https:// to run and a https:// for displaying the text of the selected XQuery. The .xq files in the file list above are shown in the combo box menu. Choosing an XQuery loads, parses, and runs the selected XQuery. The query result is shown in the bottom group box's https://.

You can write your own XQuery files and run them in the example program. The file xmlpatterns/recipes/recipes.qrc is the https:// for this example. It is used in main.cpp (Q_INIT_RESOURCE(recipes);). It lists the XQuery files (.xq) that can be selected in the combobox.

<!DOCTYPE RCC><RCC version="1.0">
<qresource>
    <file>files/cookbook.xml</file>
    <file>files/allRecipes.xq</file>
    <file>files/liquidIngredientsInSoup.xq</file>
    <file>files/mushroomSoup.xq</file>
    <file>files/preparationLessThan30.xq</file>
    <file>files/preparationTimes.xq</file>
</qresource>
</RCC>

To add your own queries to the example's combobox, store your .xq files in the examples/xmlpatterns/recipes/files directory and add them to recipes.qrc as shown above.

The example's UI is a conventional Qt GUI application inheriting https:// and the class generated by https://:

class QueryMainWindow : public QMainWindow,
                        private Ui::QueryWidget
{
    Q_OBJECT

public:
    QueryMainWindow();

public slots:
    void displayQuery(int index);

private:
    QComboBox *ui_defaultQueries = nullptr;

    void evaluate(const QString &str);
    void loadInputFile();
};

The constructor finds the window's https:// child widget and connects its https://() signal to the window's displayQuery() slot. It then calls loadInputFile() to load cookbook.xml and display its contents in the top group box's https:// . Finally, it finds the XQuery files (.xq) and adds each one to the https:// menu.

QueryMainWindow::QueryMainWindow()
{
    setupUi(this);

    new XmlSyntaxHighlighter(findChild<QTextEdit*>("inputTextEdit")->document());
    new XmlSyntaxHighlighter(findChild<QTextEdit*>("outputTextEdit")->document());

    ui_defaultQueries = findChild<QComboBox*>("defaultQueries");
    QMetaObject::connectSlotsByName(this);

    connect(ui_defaultQueries, QOverload<int>::of(&QComboBox::currentIndexChanged),
            this, &QueryMainWindow::displayQuery);

    loadInputFile();
    const QStringList queries(QDir(":/files/", "*.xq").entryList());
    for (const auto &query : queries)
        ui_defaultQueries->addItem(query);
    if (queries.count() > 0)
        displayQuery(0);
}

The work is done in the https:// slot and the https:// function it calls. https:// loads and displays the selected query file and passes the XQuery text to https://.

void QueryMainWindow::displayQuery(int index)
{
    QFile queryFile(QString(":files/") + ui_defaultQueries->itemText(index));
    queryFile.open(QIODevice::ReadOnly);
    const QString query(QString::fromLatin1(queryFile.readAll()));
    findChild<QTextEdit*>("queryTextEdit")->setPlainText(query);

    evaluate(query);
}

https:// demonstrates the standard Qt XML Patterns usage pattern. First, an instance of https:// is created (query). The query's https://() function is then called to bind the cookbook.xml file to the XQuery variable inputDocument. After the variable is bound, https://() is called to pass the XQuery text to the query.

Passing the XQuery to https://() causes Qt XML Patterns to parse the XQuery. https://() is called to ensure that the XQuery was correctly parsed.

void QueryMainWindow::evaluate(const QString &str)
{
    QFile sourceDocument;
    sourceDocument.setFileName(":/files/cookbook.xml");
    sourceDocument.open(QIODevice::ReadOnly);

    QByteArray outArray;
    QBuffer buffer(&outArray);
    buffer.open(QIODevice::ReadWrite);

    QXmlQuery query;
    query.bindVariable("inputDocument", &sourceDocument);
    query.setQuery(str);
    if (!query.isValid())
        return;

    QXmlFormatter formatter(query, &buffer);
    if (!query.evaluateTo(&formatter))
        return;

    buffer.close();
    findChild<QTextEdit*>("outputTextEdit")->setPlainText(QString::fromUtf8(outArray.constData()));

}

If the XQuery is valid, an instance of https:// is created to format the query result as XML into a https://. To evaluate the XQuery, an overload of https://() is called that takes a https:// for its output (https:// inherits https://). Finally, the formatted XML result is displayed in the UI's bottom text view.

(: All ingredients for Mushroom Soup. :)
declare variable $inputDocument external;

doc($inputDocument)/cookbook/recipe[@xml:id = "MushroomSoup"]/ingredient/
<p>{@name, @quantity}</p>

• recipes/files/allRecipes.xq

• https://

• recipes/files/liquidIngredientsInSoup.xq

• recipes/files/mushroomSoup.xq

• recipes/files/preparationLessThan30.xq

• recipes/files/preparationTimes.xq

• recipes/forms/querywidget.ui

• recipes/main.cpp

• recipes/querymainwindow.cpp

• recipes/querymainwindow.h

• recipes/recipes.pro

• recipes/recipes.qrc