# Images should be placed in <rootdir>/dic/images and examples in
# <rootdir>/examples.
# Paths are relative to the location of this file.
-exampledirs += ../doc/src
+exampledirs += src \
+ ../examples\
+ src/snippets
headerdirs += ..
imagedirs += images
sourcedirs += ..
+excludedirs += ../tests/auto \
+ ../tools
# The following parameters are for creating a qhp file, the qhelpgenerator
# program can convert the qhp file into a qch file which can be opened in
\c{main.cpp} (\c{Q_INIT_RESOURCE(queries);}). It lists the XQuery
files (\c{.xq}) that can be selected in the combobox.
- \quotefromfile examples/xmlpatterns/filetree/queries.qrc
+ \quotefromfile xmlpatterns/filetree/queries.qrc
\printuntil
To add your own queries to the example's combobox, store your
QSimpleXmlNodeModel. When you implement your own custom node model,
you must provide implementations for these callback functions:
- \snippet examples/xmlpatterns/filetree/filetree.h 0
- \snippet examples/xmlpatterns/filetree/filetree.h 1
+ \snippet xmlpatterns/filetree/filetree.h 0
+ \snippet xmlpatterns/filetree/filetree.h 1
The \c{FileTree} class declares four data members:
- \snippet examples/xmlpatterns/filetree/filetree.h 2
+ \snippet xmlpatterns/filetree/filetree.h 2
The QVector \c{m_fileInfos} will contain the node model. Each
QFileInfo in the vector will represent a file or a directory in the
types:
\target Node_Type
- \snippet examples/xmlpatterns/filetree/filetree.h 4
+ \snippet xmlpatterns/filetree/filetree.h 4
\c{Directory} and \c{File} will represent the XML element nodes for
directories and files respectively, and the other enum values will
initializes \c{m_names} with an appropriate QXmlName for each
element and attribute type:
- \snippet examples/xmlpatterns/filetree/filetree.cpp 2
+ \snippet xmlpatterns/filetree/filetree.cpp 2
Note that the constructor does \e{not} pre-build the entire node
model. Instead, the node model is built \e{incrementally} as the
a QFileInfo, the class uses the private function \c{toNodeIndex()}:
\target main toNodeIndex
- \snippet examples/xmlpatterns/filetree/filetree.cpp 1
+ \snippet xmlpatterns/filetree/filetree.cpp 1
It searches the \c{m_fileInfos} vector for a QFileInfo that matches
\c{fileInfo}. If a match is found, its array index is passed to
type directly from the QFileInfo:
\target toNodeIndex of convenience
- \snippet examples/xmlpatterns/filetree/filetree.cpp 0
+ \snippet xmlpatterns/filetree/filetree.cpp 0
Note that the auxiliary vector \c{m_names} is accessed using the
\l{Node_Type} {node type}, for example:
- \snippet examples/xmlpatterns/filetree/filetree.cpp 3
+ \snippet xmlpatterns/filetree/filetree.cpp 3
Most of the virtual functions in the callback interface are as
simple as the ones described so far, but the callback function used
each \l{QAbstractXmlNodeModel::SimpleAxis} {axis}.
\target next node on axis
- \snippet examples/xmlpatterns/filetree/filetree.cpp 4
+ \snippet xmlpatterns/filetree/filetree.cpp 4
The first thing this function does is call \l{to file info}
{toFileInfo()} to get the QFileInfo of the context node. The use of
in \c{m_fileInfos}.
\target to file info
- \snippet examples/xmlpatterns/filetree/filetree.cpp 6
+ \snippet xmlpatterns/filetree/filetree.cpp 6
The \l{QAbstractXmlNodeModel::Parent} {Parent} case looks up the
context node's parent by constructing a QFileInfo from the context
sibling to the node model, if it isn't in the model yet.
\target nextSibling helper
- \snippet examples/xmlpatterns/filetree/filetree.cpp 5
+ \snippet xmlpatterns/filetree/filetree.cpp 5
\section2 The UI Class: MainWindow
QMainWindow and the Ui_MainWindow base class generated by
\l{Qt Designer Manual} {Qt Designer}.
- \snippet examples/xmlpatterns/filetree/mainwindow.h 0
+ \snippet xmlpatterns/filetree/mainwindow.h 0
It contains the custom node model (\c{m_fileTree}) and an instance
of QXmlNodeModelIndex (\c{m_fileNode}) used for holding the node
be loaded into the custom node model. Choosing a directory signals
the \c{on_actionOpenDirectory_triggered()} slot:
- \snippet examples/xmlpatterns/filetree/mainwindow.cpp 1
+ \snippet xmlpatterns/filetree/mainwindow.cpp 1
The slot function simply calls the private function
\c{loadDirectory()} with the path of the chosen directory:
\target the standard code pattern
- \snippet examples/xmlpatterns/filetree/mainwindow.cpp 4
+ \snippet xmlpatterns/filetree/mainwindow.cpp 4
\c{loadDirectory()} demonstrates a standard code pattern for using
Qt XML Patterns programatically. First it gets the node model index
right. Choosing an XQuery signals the
\c{on_queryBox_currentIndexChanged()} slot:
- \snippet examples/xmlpatterns/filetree/mainwindow.cpp 2
+ \snippet xmlpatterns/filetree/mainwindow.cpp 2
The slot function opens and loads the query file and then calls the
private function \c{evaluateResult()} to run the query:
- \snippet examples/xmlpatterns/filetree/mainwindow.cpp 3
+ \snippet xmlpatterns/filetree/mainwindow.cpp 3
\c{evaluateResult()} is a second example of the same code pattern
shown in \l{the standard code pattern} {loadDirectory()}. In this
\c{FileTree} class, we can strip the running of \c{wholeTree.xq} out
of \l{the standard code pattern} {MainWindow::loadDirectory()}:
- \snippet examples/xmlpatterns/filetree/mainwindow.cpp 5
- \snippet examples/xmlpatterns/filetree/mainwindow.cpp 6
+ \snippet xmlpatterns/filetree/mainwindow.cpp 5
+ \snippet xmlpatterns/filetree/mainwindow.cpp 6
Note, however, that \c{FileTree} doesn't have the capability of
deleting all or part of the node model. The node model, once built,
Consider the declarations in this hypothetical C++ application:
- \snippet examples/xmlpatterns/xquery/globalVariables/globals.cpp 0
+ \snippet xmlpatterns/xquery/globalVariables/globals.cpp 0
\section3 The XML description of the C++ application
\l{http://public.kitware.com/GCC_XML/HTML/Index.html} {GCC-XML}
produces this XML description:
- \quotefromfile examples/xmlpatterns/xquery/globalVariables/globals.gccxml
+ \quotefromfile xmlpatterns/xquery/globalVariables/globals.gccxml
\printuntil
\section3 The XQuery for finding global variables
description. Here is our XQuery source. We walk through it in
\l{XQuery Code Walk-Through}.
- \quotefromfile examples/xmlpatterns/xquery/globalVariables/reportGlobals.xq
+ \quotefromfile xmlpatterns/xquery/globalVariables/reportGlobals.xq
\printuntil
\section3 Running the XQuery
\c{examples/xmlpatterns/xquery/globalVariables/reportGlobals.xq}
It begins with two variable declarations that begin the XQuery:
- \quotefromfile examples/xmlpatterns/xquery/globalVariables/reportGlobals.xq
+ \quotefromfile xmlpatterns/xquery/globalVariables/reportGlobals.xq
\skipto declare variable
\printto (:
instructions for displaying the text, and then the \c{<body>}
element.
- \quotefromfile examples/xmlpatterns/xquery/globalVariables/reportGlobals.xq
+ \quotefromfile xmlpatterns/xquery/globalVariables/reportGlobals.xq
\skipto <html xmlns
\printuntil
the two \c{return} clauses separated by the \e {comma operator}
about halfway down:
- \quotefromfile examples/xmlpatterns/xquery/globalVariables/reportGlobals.xq
+ \quotefromfile xmlpatterns/xquery/globalVariables/reportGlobals.xq
\skipto declare function local:report()
\printuntil };
Here is the html generated for the \c{<body>} element. Compare
it with the XQuery code above:
- \quotefromfile examples/xmlpatterns/xquery/globalVariables/globals.html
+ \quotefromfile xmlpatterns/xquery/globalVariables/globals.html
\skipto <body>
\printuntil </body>
returns true if the variable has a complex type. The variable can
be mutable or const.
- \quotefromfile examples/xmlpatterns/xquery/globalVariables/reportGlobals.xq
+ \quotefromfile xmlpatterns/xquery/globalVariables/reportGlobals.xq
\skipto declare function local:isComplexType
\printuntil };
\c{isPrimitive()} returns true if the variable has a primitive
type. The variable must be mutable.
- \quotefromfile examples/xmlpatterns/xquery/globalVariables/reportGlobals.xq
+ \quotefromfile xmlpatterns/xquery/globalVariables/reportGlobals.xq
\skipto declare function local:isPrimitive
\printuntil };
\c{location()} returns a text constructed from the variable's file
and line number attributes.
- \quotefromfile examples/xmlpatterns/xquery/globalVariables/reportGlobals.xq
+ \quotefromfile xmlpatterns/xquery/globalVariables/reportGlobals.xq
\skipto declare function local:location
\printuntil };
\c{main.cpp} (\c{Q_INIT_RESOURCE(recipes);}). It lists the XQuery
files (\c{.xq}) that can be selected in the combobox.
- \quotefromfile examples/xmlpatterns/recipes/recipes.qrc
+ \quotefromfile xmlpatterns/recipes/recipes.qrc
\printuntil
To add your own queries to the example's combobox, store your
QApplication. Then it creates an instance of the UI class, shows it,
and starts the Qt event loop:
- \snippet examples/xmlpatterns/recipes/main.cpp 0
+ \snippet xmlpatterns/recipes/main.cpp 0
\section2 The UI Class: QueryMainWindow
QMainWindow and the class generated by \l{Qt Designer Manual} {Qt
Designer}:
- \snippet examples/xmlpatterns/recipes/querymainwindow.h 0
+ \snippet xmlpatterns/recipes/querymainwindow.h 0
The constructor finds the window's \l{QComboBox} {combo box} child
widget and connects its \l{QComboBox::currentIndexChanged()}
viewer} . Finally, it finds the XQuery files (\c{.xq}) and adds each
one to the \l{QComboBox} {combo box} menu.
- \snippet examples/xmlpatterns/recipes/querymainwindow.cpp 0
+ \snippet xmlpatterns/recipes/querymainwindow.cpp 0
The work is done in the \l{displayQuery() slot} {displayQuery()}
slot and the \l{evaluate() function} {evaluate()} function it
function} {evaluate()}.
\target displayQuery() slot
- \snippet examples/xmlpatterns/recipes/querymainwindow.cpp 1
+ \snippet xmlpatterns/recipes/querymainwindow.cpp 1
\l{evaluate() function} {evaluate()} demonstrates the standard
Qt XML Patterns usage pattern. First, an instance of QXmlQuery is
called to ensure that the XQuery was correctly parsed.
\target evaluate() function
- \snippet examples/xmlpatterns/recipes/querymainwindow.cpp 2
+ \snippet xmlpatterns/recipes/querymainwindow.cpp 2
If the XQuery is valid, an instance of QXmlFormatter is created to
format the query result as XML into a QBuffer. To evaluate the
QApplication. Then it creates an instance of the mainwindow class, shows it,
and starts the Qt event loop:
- \snippet examples/xmlpatterns/schema/main.cpp 0
+ \snippet xmlpatterns/schema/main.cpp 0
\section2 The UI Class: MainWindow
QMainWindow and the class generated by \l{Qt Designer Manual} {Qt
Designer}:
- \snippet examples/xmlpatterns/schema/mainwindow.h 0
+ \snippet xmlpatterns/schema/mainwindow.h 0
The constructor fills the schema and instance \l{QComboBox} selections with the predefined
schemas and instances and connects their \l{QComboBox::currentIndexChanged()} {currentIndexChanged()}
The call to \c{schemaSelected(0)} and \c{instanceSelected(0)} will trigger the validation
of the initial Contact Schema example.
- \snippet examples/xmlpatterns/schema/mainwindow.cpp 0
+ \snippet xmlpatterns/schema/mainwindow.cpp 0
In the \c{schemaSelected()} slot the content of the instance \l{QComboBox} {selection}
is adapted to the selected schema and the corresponding schema is loaded from the
\l{The Qt Resource System} {resource file} and displayed in the schema \l{QTextBrowser} {viewer}.
At the end of the method a revalidation is triggered.
- \snippet examples/xmlpatterns/schema/mainwindow.cpp 1
+ \snippet xmlpatterns/schema/mainwindow.cpp 1
In the \c{instanceSelected()} slot the selected instance is loaded from the
\l{The Qt Resource System} {resource file} and loaded into the instance \l{QTextEdit} {editor}
an the revalidation is triggered again.
- \snippet examples/xmlpatterns/schema/mainwindow.cpp 2
+ \snippet xmlpatterns/schema/mainwindow.cpp 2
The \c{validate()} slot does the actual work in this example.
At first it stores the content of the schema \l{QTextBrowser} {viewer} and the
\l{QAbstractMessageHandler} {QAbstractMessageHandler} and is a convenience
class to store error messages from the XmlPatterns system.
- \snippet examples/xmlpatterns/schema/mainwindow.cpp 4
+ \snippet xmlpatterns/schema/mainwindow.cpp 4
After the \l{QXmlSchema} {QXmlSchema} is instanciated and the message handler set
on it, the \l{QXmlSchema::load()} {load()} method is called with the schema data as argument.
The rest of the code does only some fancy coloring and eyecandy.
- \snippet examples/xmlpatterns/schema/mainwindow.cpp 3
+ \snippet xmlpatterns/schema/mainwindow.cpp 3
*/
As a result we get the following document:
- \quotefile examples/xmlpatterns/trafficinfo/time_example.wml
+ \quotefile xmlpatterns/trafficinfo/time_example.wml
So for every departure we have a \c <a> tag that contains the time as a
text element, and the following text element contains the line number
that takes a station ID and date/time as input and returns the list of
times and directions:
- \snippet examples/xmlpatterns/trafficinfo/timequery.cpp 1
+ \snippet xmlpatterns/trafficinfo/timequery.cpp 1
The first lines of this function synthesize the XQuery strings that fetch
the document and extract the data.
will return the following document:
- \snippet examples/xmlpatterns/trafficinfo/station_example.wml 0
+ \snippet xmlpatterns/trafficinfo/station_example.wml 0
The names of the available stations are listed as separate text elements
and the station ID is part of the \c href attribute of the parent \c a
the action of querying the stations that match the given name pattern with
the following code:
- \snippet examples/xmlpatterns/trafficinfo/stationquery.cpp 0
+ \snippet xmlpatterns/trafficinfo/stationquery.cpp 0
Just as in the \c TimeQuery implementation, the first step is to
synthesize the XQuery strings for selecting the station names and the
library:
\target qtxmlpatterns_example_query
- \quotefile snippets/patternist/introductionExample.xq
+ \quotefile patternist/introductionExample.xq
First, the query opens a \c{<bibliography>} element in the
output. The
\c{myquery.xq}), we can run it from a Qt application using a
standard Qt XML Patterns code sequence:
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qxmlquery.cpp 3
+ \snippet code/src_xmlpatterns_api_qxmlquery.cpp 3
First construct a QFile for the text file containing the XQuery
(\c{myquery.xq}). Then create an instance of QXmlQuery and call
\e xmlpatterns is a command line utility for running XQueries. It
expects the name of a file containing the XQuery text.
- \snippet doc/src/snippets/code/doc_src_qtxmlpatterns.qdoc 2
+ \snippet code/doc_src_qtxmlpatterns.qdoc 2
The XQuery in \c{myQuery.xq} will be evaluated and its output
written to \c stdout. Pass the \c -help switch to get the list of
(\c{$publisher}), and the year of publication (\c{$year}):
\target qtxmlpatterns_example_query2
- \quotefile snippets/patternist/introExample2.xq
+ \quotefile patternist/introExample2.xq
Modify the Qt XML Patterns code to use one of the \l{QXmlQuery::}
{bindVariable()} functions to bind a program variable to each
XQuery $variable:
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qxmlquery.cpp 4
+ \snippet code/src_xmlpatterns_api_qxmlquery.cpp 4
Each program variable is passed to Qt XML Patterns as a QVariant of
the type of the C++ variable or constant from which it is
populates a sequence of \l {QXmlResultItems} {result items} with
the XQuery results:
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qxmlquery.cpp 5
+ \snippet code/src_xmlpatterns_api_qxmlquery.cpp 5
Iterate through the \l {QXmlResultItems} {result items} and test
each QXmlItem to see if it is an atomic value or a node. If it is
friend of QMetaType (qMetaTypeId<T>()) and a friend of QVariant
(qvariant_cast<T>()):
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qxmlquery.cpp 6
+ \snippet code/src_xmlpatterns_api_qxmlquery.cpp 6
To access the strings in a QXmlName returned by an
\l{QXmlQuery::evaluateTo()} {XQuery evaluation}, the QXmlName must
to find all the skin care product orders and output them ordered
by shipping date.
- \quotefile snippets/patternist/introAcneRemover.xq
+ \quotefile patternist/introAcneRemover.xq
Qt XML Patterns can be used out of the box to perform this
query, provided \e myOrders.xml actually contains well-formed XML. It
description of it. Such an XML file, if it existed, might look
something like this:
- \quotefile snippets/patternist/introFileHierarchy.xml
+ \quotefile patternist/introFileHierarchy.xml
The \l{File System Example}{File System Example} does exactly this.
Now we can write an XQuery to find all the XML files and parse
them to find the ones that don't contain well-formed XML.
- \quotefromfile snippets/patternist/introNavigateFS.xq
+ \quotefromfile patternist/introNavigateFS.xq
\skipto <html>
\printuntil
Consider the following example:
- \snippet doc/src/snippets/code/doc_src_qtxml.qdoc 6
+ \snippet code/doc_src_qtxml.qdoc 6
Here we find three different uses of the name \e title. If you wish to
process this document you will encounter problems because each of the
occurrence of \e title as the title of a book, i.e. to use the \e
title element of a book namespace to distinguish it from, for example,
the chapter title, e.g.:
- \snippet doc/src/snippets/code/doc_src_qtxml.qdoc 7
+ \snippet code/doc_src_qtxml.qdoc 7
\e book in this case is a \e prefix denoting the namespace.
http://www.example.com/fnord/ the document's default XML namespace \e
xmlns we write
- \snippet doc/src/snippets/code/doc_src_qtxml.qdoc 8
+ \snippet code/doc_src_qtxml.qdoc 8
To distinguish the \e http://www.example.com/fnord/book/ namespace from
the default, we must supply it with a prefix:
- \snippet doc/src/snippets/code/doc_src_qtxml.qdoc 9
+ \snippet code/doc_src_qtxml.qdoc 9
A namespace that is declared like this can be applied to element and
attribute names by prepending the appropriate prefix and a ":"
within a \e chapter.
Let's clarify this with an example:
- \snippet doc/src/snippets/code/doc_src_qtxml.qdoc 10
+ \snippet code/doc_src_qtxml.qdoc 10
Within the \e document element we have two namespaces declared. The
default namespace \e http://www.example.com/fnord/ applies to the \e
or an end tag, etc.
To make it less abstract consider the following example:
- \snippet doc/src/snippets/code/doc_src_qtxml.qdoc 3
+ \snippet code/doc_src_qtxml.qdoc 3
Whilst reading (a SAX2 parser is usually referred to as "reader")
the above document three events would be triggered:
and switched on or off using QXmlReader::setFeature().
Consider the example
- \snippet doc/src/snippets/code/doc_src_qtxml.qdoc 4
+ \snippet code/doc_src_qtxml.qdoc 4
A reader that does not support the \e
http://xml.org/sax/features/namespace-prefixes feature would report
the element name \e document but not its attributes \e xmlns:book and
\endlist
Consider the following element:
- \snippet doc/src/snippets/code/doc_src_qtxml.qdoc 5
+ \snippet code/doc_src_qtxml.qdoc 5
With \e http://xml.org/sax/features/namespace-prefixes set to true
the reader will report four attributes; but with the \e
namespace-prefixes feature set to false only three, with the \e
language is \e{expression-based}. The simplest XQuery expression is an
XML element constructor:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 20
+\snippet code/doc_src_qtxmlpatterns.qdoc 20
This \c{<recipe/>} element is an XQuery expression that forms a
complete XQuery. In fact, this XQuery doesn't actually query
in another XQuery expression. This XQuery has a document expression
embedded in a node expression:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 21
+\snippet code/doc_src_qtxmlpatterns.qdoc 21
It creates a new \c{<html>} element in the output and sets its \c{id}
attribute to be the \c{id} attribute from an \c{<html>} element in the
that child node will represent the document element. Consider the
following XQuery:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 18
+\snippet code/doc_src_qtxmlpatterns.qdoc 18
The \c{doc()} function loads the \c{cookbook.xml} file and returns the
document node. The document node then becomes the focus for the next
to iterating through the same number of nested \e{for} loops. Consider
the following XQuery, which builds on the previous one:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 19
+\snippet code/doc_src_qtxmlpatterns.qdoc 19
This XQuery is a single path expression composed of three steps. The
first step creates the initial focus by calling the \c{doc()}
they can also be written in the longhand form. If we rewrite the
XQuery in the longhand form, it looks like this:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 22
+\snippet code/doc_src_qtxmlpatterns.qdoc 22
The two axis steps have been expanded. The first step (\c{//recipe})
has been rewritten as \c{/descendant-or-self::element(recipe)}, where
parameter. A name test must match the node \e name in addition to the
node \e kind. We have already seen name tests used:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 19
+\snippet code/doc_src_qtxmlpatterns.qdoc 19
In this path expression, both \c{recipe} and \c{title} are name tests
written in the shorthand form. XQuery resolves these names
add a \e{default} namespace to \c{cookbook.xml} now. Change the
\e{document element} in \c{cookbook.xml} from:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 23
+\snippet code/doc_src_qtxmlpatterns.qdoc 23
to...
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 24
+\snippet code/doc_src_qtxmlpatterns.qdoc 24
This is called a \e{default namespace} declaration because it doesn't
include a namespace prefix. By including this default namespace
prefix} (e.g. \c{c} for cookbook) and prefix each name test with the
namespace prefix:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 3
+\snippet code/doc_src_qtxmlpatterns.qdoc 3
Or we can declare the namespace to be the \e{default element
namespace}, and then we can still run the original XQuery:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 4
+\snippet code/doc_src_qtxmlpatterns.qdoc 4
Both methods will work and produce the same output, all the
\c{<title>} elements:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 5
+\snippet code/doc_src_qtxmlpatterns.qdoc 5
But note how the output is slightly different from the output we saw
before we added the default namespace declaration to the cookbook file.
namespace, use the \c{xml:} namespace prefix but replace the
\e{local name} (the attribute name) with the wildcard:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 7
+\snippet code/doc_src_qtxmlpatterns.qdoc 7
Oops! If you save this XQuery in \c{file.xq} and run it through
\c{xmlpatterns}, it doesn't work. You get an error message instead,
the wildcard and write \c{name} (the attribute name) as the local
name:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 8
+\snippet code/doc_src_qtxmlpatterns.qdoc 8
To find and select all the attributes of the \e{document element} in
the cookbook, replace the entire name test with the wildcard:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 9
+\snippet code/doc_src_qtxmlpatterns.qdoc 9
\section1 Using Predicates In Path Expressions
selects the recipe element that has the \c{<title>} element
\c{"Hard-Boiled Eggs"}.
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 10
+\snippet code/doc_src_qtxmlpatterns.qdoc 10
The dot expression ('.') can be used in predicates and path
expressions to refer to the current context node. The following query
uses the dot expression to refer to the current \c{<method>} element.
The query selects the empty \c{<method>} elements from the cookbook.
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 11
+\snippet code/doc_src_qtxmlpatterns.qdoc 11
Note that passing the dot expression to the
\l{http://www.w3.org/TR/xpath-functions/#func-string-length}
{string-length()} is called with no parameter, the context node is
assumed:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 12
+\snippet code/doc_src_qtxmlpatterns.qdoc 12
Actually, selecting an empty \c{<method>} element might not be very
useful by itself. It doesn't tell you which recipe has the empty
method:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 31
+\snippet code/doc_src_qtxmlpatterns.qdoc 31
\target Empty Method Not Robust
What you probably want to see instead are the \c{<recipe>} elements that
have empty \c{<method>} elements:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 32
+\snippet code/doc_src_qtxmlpatterns.qdoc 32
The predicate uses the
\l{http://www.w3.org/TR/xpath-functions/#func-string-length}
element is discarded. The output is the entire recipe that has no
instructions for preparation:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 33
+\snippet code/doc_src_qtxmlpatterns.qdoc 33
The astute reader will have noticed that this use of
\c{string-length()} to find an empty element is unreliable. It works
This query returns the second \c{<recipe>} element in the
\c{cookbook.xml} file:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 13
+\snippet code/doc_src_qtxmlpatterns.qdoc 13
The other frequently used positional function is
\l{http://www.w3.org/TR/xpath-functions/#func-last} {last()}, which
{last()} returns the size of the focus set. This query returns the
last recipe in the cookbook:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 16
+\snippet code/doc_src_qtxmlpatterns.qdoc 16
And this query returns the next to last \c{<recipe>}:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 17
+\snippet code/doc_src_qtxmlpatterns.qdoc 17
\section2 Boolean Predicates
there was whitespace between the tags. Here is a more robust way that
uses a different boolean predicate.
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 34
+\snippet code/doc_src_qtxmlpatterns.qdoc 34
This one uses the
\l{http://www.w3.org/TR/xpath-functions/#func-empty} {empty()} and
a recipe with no instructions that won't be detected. There is a
better way:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 35
+\snippet code/doc_src_qtxmlpatterns.qdoc 35
This version uses the
\l{http://www.w3.org/TR/xpath-functions/#func-not} {not} and
function returns the position index of the current context item in the
sequence of items:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 14
+\snippet code/doc_src_qtxmlpatterns.qdoc 14
Note that the first position in the sequence is position 1, not 0. We
can also select \e{all} the recipes after the first one:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 15
+\snippet code/doc_src_qtxmlpatterns.qdoc 15
\target Constructing Elements
\section1 Constructing Elements
\l{http://www.w3.org/TR/xquery/#id-orderby-return} {\e{return}
clause} with an element constructor:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 25
+\snippet code/doc_src_qtxmlpatterns.qdoc 25
The \e{for} clause produces a sequence of attribute nodes from the result
of the path expression. Each attribute node in the sequence is bound
to the variable \c{$i}. The \e{return} clause then constructs a \c{<p>}
element around the attribute node. Here is the output:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 28
+\snippet code/doc_src_qtxmlpatterns.qdoc 28
The output contains one \c{<p>} element for each \c{xml:id} attribute
in the cookbook. Note that XQuery puts each attribute in the right
section can be rewritten the same way. Here is the XQuery that selects
all the \c{name} attributes, regardless of namespace:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 26
+\snippet code/doc_src_qtxmlpatterns.qdoc 26
And here is its output:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 29
+\snippet code/doc_src_qtxmlpatterns.qdoc 29
And here is the XQuery that selects all the attributes from the
\e{document element}:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 27
+\snippet code/doc_src_qtxmlpatterns.qdoc 27
And here is its output:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 30
+\snippet code/doc_src_qtxmlpatterns.qdoc 30
\section2 Element Constructors are Expressions
Because node constructors are expressions, they can be used in
XQueries wherever expressions are allowed.
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 40
+\snippet code/doc_src_qtxmlpatterns.qdoc 40
If \c{cookbook.xml} is loaded without error, a \c{<oppskrift>} element
(Norwegian word for recipe) is constructed for each \c{<recipe>}
To construct an atomic value as element content, enclose an expression
in curly braces and embed it in the element constructor:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 36
+\snippet code/doc_src_qtxmlpatterns.qdoc 36
Sending this XQuery through xmlpatterns produces:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 37
+\snippet code/doc_src_qtxmlpatterns.qdoc 37
To compute the value of an attribute, enclose the expression in
curly braces and embed it in the attribute value:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 38
+\snippet code/doc_src_qtxmlpatterns.qdoc 38
Sending this XQuery through xmlpatterns produces:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 39
+\snippet code/doc_src_qtxmlpatterns.qdoc 39
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 40
+\snippet code/doc_src_qtxmlpatterns.qdoc 40
If \c{cookbook.xml} is loaded without error, a \c{<oppskrift>} element
(Norweigian word for recipe) is constructed for each \c{<recipe>}
cookbook XQuery examples in a \c{.xq} file (e.g., \c{file.xq}), and
run the XQuery using Qt's command line utility:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 6
+\snippet code/doc_src_qtxmlpatterns.qdoc 6
\section1 Further Reading
namespaces in your XQuery. Consider the following query for selecting
all the examples in an XHTML document:
-\quotefile snippets/patternist/simpleHTML.xq
+\quotefile patternist/simpleHTML.xq
It won't match anything because \c{index.html} is an XHTML file, and
all XHTML files declare the default namespace
\c{{http://www.w3.org/1999/xhtml}html}. One possible fix is to declare the
correct default namespace in the XQuery:
-\quotefile snippets/patternist/simpleXHTML.xq
+\quotefile patternist/simpleXHTML.xq
Another common cause of this bug is to confuse the \e{document node}
with the top element node. They are different. This query won't match
anything:
-\quotefile snippets/patternist/docPlainHTML.xq
+\quotefile patternist/docPlainHTML.xq
The \c{doc()} function returns the \e{document node}, not the top
element node (\c{<html>}). Don't forget to match the top element node
in the path expression:
-\quotefile snippets/patternist/docPlainHTML2.xq
+\quotefile patternist/docPlainHTML2.xq
\section2 What if my input namespace is different from my output namespace?
properly. Consider the following query, which is meant to generate
XHTML output from XML input:
-\quotefile snippets/patternist/embedDataInXHTML.xq
+\quotefile patternist/embedDataInXHTML.xq
We want the \c{<html>}, \c{<body>}, and \c{<p>} nodes we create in the
output to be in the standard XHTML namespace, so we declare the
namespace prefix, and then use the prefix with the node names in
the path expression. This one will probably work better:
-\quotefile snippets/patternist/embedDataInXHTML2.xq
+\quotefile patternist/embedDataInXHTML2.xq
\section2 Why doesn't my return clause work?
understanding XQuery expression precedence is very important.
Consider the following query:
-\quotefile snippets/patternist/forClause2.xq
+\quotefile patternist/forClause2.xq
It looks ok, but it isn't. It is supposed to be a FLWOR expression
comprising a \e{for} clause and a \e{return} clause, but it isn't just
scope error will be reported. Correct these problems by using
parentheses.
-\quotefile snippets/patternist/forClause.xq
+\quotefile patternist/forClause.xq
\section2 Why didn't my expression get evaluated?
expression, or you forgot to add some parentheses. Consider this
input file \c{doc.txt}:
-\quotefile snippets/patternist/doc.txt
+\quotefile patternist/doc.txt
Suppose you want the first \c{<span>} element of every \c{<p>}
element. Apply a position filter (\c{[1]}) to the \c{/span} path step:
-\quotefile snippets/patternist/filterOnStep.xq
+\quotefile patternist/filterOnStep.xq
Applying the \c{[1]} filter to the \c{/span} step returns the first
\c{<span>} element of each \c{<p>} element:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 41
+\snippet code/doc_src_qtxmlpatterns.qdoc 41
\note: You can write the same query this way:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 44
+\snippet code/doc_src_qtxmlpatterns.qdoc 44
Or you can reduce it right down to this:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 45
+\snippet code/doc_src_qtxmlpatterns.qdoc 45
On the other hand, suppose you really want only one \c{<span>}
element, the first one in the document (i.e., you only want the first
\c{[1]} filter in the same place as above but enclose the path
expression in parentheses:
-\quotefile snippets/patternist/filterOnPath.xq
+\quotefile patternist/filterOnPath.xq
Or you can apply a second position filter (\c{[1]} again) to the
\c{/p} path step:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 43
+\snippet code/doc_src_qtxmlpatterns.qdoc 43
Either way the query will return only the first \c{<span>} element in
the document:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 42
+\snippet code/doc_src_qtxmlpatterns.qdoc 42
\section2 Why doesn't my FLWOR behave as expected?
just like a C++ \e{for} loop. But they aren't the same. Consider a
simple example:
-\quotefile snippets/patternist/letOrderBy.xq
+\quotefile patternist/letOrderBy.xq
This query evaluates to \e{4 -4 -2 2 -8 8}. The \e{for} clause does
set up a \e{for} loop style iteration, which does evaluate the rest of
8) on the third iteration. So the following query doesn't iterate
through anything, and doesn't do any ordering:
-\quotefile snippets/patternist/invalidLetOrderBy.xq
+\quotefile patternist/invalidLetOrderBy.xq
It binds the entire sequence (2, 3, 1) to \c{$i} one time only; the
\e{order by} clause only has one thing to order and hence does
there is no correct order. Consider the following query,
which again uses the input file \c{doc.txt}:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 46
+\snippet code/doc_src_qtxmlpatterns.qdoc 46
The query finds all the \c{<p>} elements in the file. For each \c{<p>}
element, it builds a \c{<p>} element in the output containing the
elements. Running the query through \c{xmlpatterns} might produce the
following output, which is not sorted in the expected order.
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 47
+\snippet code/doc_src_qtxmlpatterns.qdoc 47
You can use a \e{for} loop to ensure that the order of
the result set corresponds to the order of the input sequence:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 48
+\snippet code/doc_src_qtxmlpatterns.qdoc 48
This version produces the same result set but in the expected order:
-\snippet snippets/code/doc_src_qtxmlpatterns.qdoc 49
+\snippet code/doc_src_qtxmlpatterns.qdoc 49
\section2 Why can't I use \c{true} and \c{false} in my XQuery?
you want to use \c{true} and \c{false}. The other way is to invoke the
boolean constructor:
-\quotefile snippets/patternist/xsBooleanTrue.xq
+\quotefile patternist/xsBooleanTrue.xq
*/
about resolving the \a relative URI, it should simply return the \a
relative URI resolved against the \a baseURI, i.e.:
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qabstracturiresolver.cpp 0
+ \snippet code/src_xmlpatterns_api_qabstracturiresolver.cpp 0
\sa QUrl::isRelative(), QUrl::isValid()
*/
that is converted to OutputType by calling a function on Derived
that has the following signature:
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qabstractxmlforwarditerator.cpp 0
+ \snippet code/src_xmlpatterns_api_qabstractxmlforwarditerator.cpp 0
TODO Document why this class doesn't duplicate ItemMappingIterator.
*/
present it through the \l
{http://www.w3.org/TR/xpath-datamodel/}{XPath Data Model interface}.
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qabstractxmlnodemodel.cpp 1
+ \snippet code/src_xmlpatterns_api_qabstractxmlnodemodel.cpp 1
The application first creates an instance of QXmlQuery and calls \l
{QXmlQuery::setQuery()}{setQuery()} to read \c queryFile containing
each item is either an XML node or an atomic value. The query in the
following snippet evaluates to sequence of five items.
- \quotefile doc/src/snippets/patternist/items.xq
+ \quotefile patternist/items.xq
The five items are: An element, an atomic value (binary data encoded
in base64), a date, a float, and an attribute.
Resets this QXmlNodeModelIndex to be null. It is equivalent to
writing:
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qabstractxmlnodemodel.cpp 0
+ \snippet code/src_xmlpatterns_api_qabstractxmlnodemodel.cpp 0
*/
/*!
transforming that sequence into a structure of your choosing,
usually XML. Consider the example:
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qabstractxmlreceiver.cpp 0
+ \snippet code/src_xmlpatterns_api_qabstractxmlreceiver.cpp 0
First it constructs a \l {QXmlQuery} {query} that gets the
first paragraph from document \c index.html. Then it constructs
processing instruction to tell the application to use a
particular XSLT stylesheet to process the document.
- \quotefile doc/src/snippets/patternist/xmlStylesheet.xq
+ \quotefile patternist/xmlStylesheet.xq
\a target is the \l {QXmlName} {name} of the processing
instruction. Its \e prefix and \e {namespace URI} must both
For example, where the base class QXmlSerializer would
output this:
- \quotefile doc/src/snippets/patternist/notIndented.xml
+ \quotefile patternist/notIndented.xml
QXmlFormatter outputs this:
- \quotefile doc/src/snippets/patternist/indented.xml
+ \quotefile patternist/indented.xml
If you just want to serialize your XML in a human-readable
format, use QXmlFormatter as it is. The default indentation
Alternatively, you can subclass QXmlFormatter and reimplement
the callbacks there.
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qxmlformatter.cpp 0
+ \snippet code/src_xmlpatterns_api_qxmlformatter.cpp 0
*/
/*!
URI}, the \e {local name}, and the \e {prefix}. To see what these
refer to in XML, consider the following snippet.
- \quotefile doc/src/snippets/patternist/mobeyDick.xml
+ \quotefile patternist/mobeyDick.xml
For the element named \e book, localName() returns \e book,
namespaceUri() returns \e http://example.com/MyDefault,
used in name comparisons. For example, the following two element
nodes represent the same element and compare equal.
- \quotefile doc/src/snippets/patternist/svgDocumentElement.xml
+ \quotefile patternist/svgDocumentElement.xml
- \quotefile doc/src/snippets/patternist/xsvgDocumentElement.xml
+ \quotefile patternist/xsvgDocumentElement.xml
Although the second name has the prefix \e x, the two names compare
equal as instances of QXmlName, because the prefix is not used in
Setting of the mask enums use essentially this:
- \quotefile doc/src/snippets/code/src_xmlpatterns_api_qxmlname.cpp
+ \quotefile code/src_xmlpatterns_api_qxmlname.cpp
The masks, such as LocalNameMask, are positive. That is, for the
area which the name resides, the bits are set.
{http://www.w3.org/TR/xpath-datamodel/} {XQuery 1.0 and XPath 2.0
Data Model}.
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qabstractxmlreceiver.cpp 0
+ \snippet code/src_xmlpatterns_api_qabstractxmlreceiver.cpp 0
The example uses QXmlQuery to match the first paragraph of an XML
document and then \l {QXmlSerializer} {output the result} to a
an XSLT stylesheet instead of as an XQuery. You must also set the
input document by calling setFocus().
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qxmlquery.cpp 7
+ \snippet code/src_xmlpatterns_api_qxmlquery.cpp 7
\note Currently, setFocus() must be called \e before setQuery() when
using XSLT.
query's \l {QXmlNamePool} {namespace}. The function then behaves as
the overloaded function. It is equivalent to the following snippet.
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qxmlquery.cpp 0
+ \snippet code/src_xmlpatterns_api_qxmlquery.cpp 0
*/
void QXmlQuery::bindVariable(const QString &localName, const QXmlItem &value)
{
this function can be used to pass an XML document in memory to
\c{fn:doc}.
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qxmlquery.cpp 1
+ \snippet code/src_xmlpatterns_api_qxmlquery.cpp 1
The caller must ensure that \a device has been opened with at least
QIODevice::ReadOnly prior to this binding. Otherwise, behavior is
a QBuffer as shown in the following snippet. Suppose \e myQString
contains \c{<document>content</document>}
- \snippet doc/src/snippets/qxmlquery/bindingExample.cpp 0
+ \snippet qxmlquery/bindingExample.cpp 0
\a name must not be \e null. \a {name}.isNull() must return false.
If \a name has already been bound, its previous binding will be
If \a localName is a valid \l {QXmlName::isNCName()} {NCName}, this
function is equivalent to the following snippet.
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qxmlquery.cpp 2
+ \snippet code/src_xmlpatterns_api_qxmlquery.cpp 2
A QXmlName is constructed from \a localName, and is passed
to the appropriate overload along with \a device.
repeatedly calling next(), which actually produces the sequence by
lazy evaluation of the query.
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qxmlresultitems.cpp 0
+ \snippet code/src_xmlpatterns_api_qxmlresultitems.cpp 0
An effect of letting next() produce the sequence by lazy evaluation
is that a query error can occur on any call to next(). If an error
The following example shows how to load a XML Schema file from the network
and test whether it is a valid schema document:
- \snippet doc/src/snippets/qxmlschema/main.cpp 0
+ \snippet qxmlschema/main.cpp 0
\section1 XML Schema Version
Example:
- \snippet doc/src/snippets/qxmlschema/main.cpp 0
+ \snippet qxmlschema/main.cpp 0
\sa isValid()
*/
Example:
- \snippet doc/src/snippets/qxmlschema/main.cpp 1
+ \snippet qxmlschema/main.cpp 1
\sa isValid()
*/
Example:
- \snippet doc/src/snippets/qxmlschema/main.cpp 2
+ \snippet qxmlschema/main.cpp 2
\sa isValid()
*/
file, check whether it is a valid schema document and use it for validation
of an XML instance document:
- \snippet doc/src/snippets/qxmlschemavalidator/main.cpp 3
+ \snippet qxmlschemavalidator/main.cpp 3
\section1 XML Schema Version
Example:
- \snippet doc/src/snippets/qxmlschemavalidator/main.cpp 2
+ \snippet qxmlschemavalidator/main.cpp 2
*/
bool QXmlSchemaValidator::validate(const QByteArray &data, const QUrl &documentUri) const
{
Example:
- \snippet doc/src/snippets/qxmlschemavalidator/main.cpp 0
+ \snippet qxmlschemavalidator/main.cpp 0
*/
bool QXmlSchemaValidator::validate(const QUrl &source) const
{
Example:
- \snippet doc/src/snippets/qxmlschemavalidator/main.cpp 1
+ \snippet qxmlschemavalidator/main.cpp 1
*/
bool QXmlSchemaValidator::validate(QIODevice *source, const QUrl &documentUri) const
{
QXmlSerializer translates an \l {XQuery Sequence} {XQuery sequence}, usually
the output of an QXmlQuery, into XML. Consider the example:
- \snippet doc/src/snippets/code/src_xmlpatterns_api_qxmlserializer.cpp 0
+ \snippet code/src_xmlpatterns_api_qxmlserializer.cpp 0
First it constructs a \l {QXmlQuery} {query} that gets the
first paragraph from document \c index.html. Then it constructs
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