XML functions

xf:attribute() / xxf:attribute()

This function is available in both the xf and xxf namespaces, and we recommend you use it with the xf namespace.

xf:attribute(
$qname as xs:anyAtomicType
) as attribute()
xf:attribute(
$qname as xs:anyAtomicType,
$value as xs:anyAtomicType?
) as attribute()

The xf:attribute() function returns a new XML attribute with the qualified name provided as first argument. If the qualified name is not of type xs:QName, its string value is used. If it has a prefix, it is resolved using in-scope namespaces. The second argument is an optional value for the attribute. It defaults to the empty string.

<!-- Add an attribute called "id" with a value of "first-name" to element "section" -->
<xf:insert
context="section"
origin="xf:attribute('id', 'first-name')"/>

The first argument can be of type xs:QName:

<!-- Add an attribute called "id" with a value of "foo:bar" to element "section"
and resolve the namespaces on element $element -->
<xf:insert
context="section"
origin="xf:attribute(resolve-QName('foo:bar', $element), 'first-name')"/>

xxf:call-xpl()

xxf:call-xpl(
$xplURL as xs:string,
$inputNames as xs:string*,
$inputElements as element()*,
$outputNames as xs:string+
) as document-node()*

This function lets you call an XPL pipeline.

  • $xplURL is the URL of the pipeline. It must be an absolute URL.

  • $inputNames is a sequence of strings, each one representing the name of an input of the pipeline that you want to connect.

  • $inputElements is a sequence of elements to be used as input for the pipeline. The $inputNames and $inputElements sequences must have the same length. For each element in $inputElements, a document is created and connected to an input of the pipeline. Elements are matched to input name by position, for instance the element at position 3 of $inputElements is connected to the input with the name specified at position 3 in $inputNames.

  • $outputNames is a sequence of output names to read.

The function returns a sequence of document nodes corresponding the output of the pipeline. The returned sequence will have the same length as $outputNames and will correspond to the pipeline output with the name specified on $outputNames based on position.

The example below shows a call to the xxf:call-xpl function, calling a pipeline with two inputs and one output:

xxf:call-xpl(
'oxf:/examples/sandbox/xpath/run-xpath.xpl',
(
'input',
'xpath'
),
(
instance('instance')/input,
instance('instance')/xpath
),
'html'
)

xxf:classes()

xxf:classes() as xs:boolean
xxf:classes($el as node()) as xs:string*

Returns for the context element or the given element if provided, all the classes on the class attribute.

xxf:create-document()

xxf:create-document() as document-node()

The xxf:create-document() creates a new empty XML document. You can then insert new data into that document with the xf:insert action.

<xf:var name="new" value="xxf:create-document()"/>
<xf:insert context="$new" origin="instance('my-data')"/>

xf:element() / xxf:element()

This function is available in both the xf and xxf namespaces, and we recommend you use it with the xf namespace.

xf:element(
$element-name as xs:anyAtomicType
) as element()
xf:element(
$element-name as xs:anyAtomicType,
$content as item()*
) as element()

The xf:element() function returns a new XML element with the qualified name provided. If the qualified name is not of type xs:QName, its string value is used. If it has a prefix, it is resolved using in-scope namespaces.

<!-- Insert an element called "value" as a child of element "section" -->
<xf:insert
context="section"
origin="xf:element('value')">

The second, optional argument can take a sequence of items specifying attributes and content for the new element:

<!-- Insert an element called "value" as a child of element "section",
with an attribute and text content -->
<xf:insert
context="section"
origin="xf:element('value', (xf:attribute('id', 'my-value'), 'John'))"/>

The first argument can be of type xs:QName:

<!-- Insert an element called "foo:bar" as a child of element "section"
and resolve the namespaces on element $element -->
<xf:insert
context="section"
origin="xf:element(resolve-QName('foo:bar', $element))"/>

xxf:evaluate()

xxf:evaluate(
$xpath as xs:string
) as item()*

The xxf:evaluate() function allows you to evaluate XPath expressions dynamically. For example:

<xf:input ref="xxf:evaluate(concat('instance(''my-instance'')/document', my-xpath))">
<xf:label>...</xf:label>
</xf:input>

xxf:extract-document()

xxf:extract-document(
$element as element()
) as document-node()
xxf:extract-document(
$element as element(),
$excludeResultPrefixes as xs:boolean
) as document-node()
xxf:extract-document(
$element as element(),
$excludeResultPrefixes as xs:boolean,
$readonly as xs:boolean
) as document-node()

The xxf:extract-document() function extracts a new XML document from a document fragment under an enclosing element. For example with the following instance:

<xf:instance id="my-instance">
<library>
<book>
<title>Jacques le fataliste et son maître</title>
<author>Denis Diderot</author>
</book>
</library>
</xf:instance>

The expression:

xxf:extract-document(instance('my-instance')/book, '', false())

returns a new XML document rooted at the <book> element:

<book>
<title>Jacques le fataliste et son maître</title>
<author>Denis Diderot</author>
</book>
  • $excludeResultPrefixes: optional parameter; contains a list of space-separated namespace prefixes to exclude. Defaults to the empty string.

  • $readonly: optional parameter; when set to true(), return a readonly instance. Defaults to false().

xxf:form-urlencode()

xxf:form-urlencode($document as node()) as xs:string

Performs application/x-www-form-urlencoded encoding on an XML document as per the XForms specification.

xxf:has-class()

xxf:has-class($class-name as xs:string) as xs:boolean
xxf:has-class($class-name as xs:string, $el as node()) as xs:boolean

Returns whether the context element, or the given element, has a class attribute containing the specified class name.

xxf:mutable-document()

xxf:mutable-document(
$node as node()
) as document-node()

The xxf:mutable-document() function takes a document as input and returns a mutable document, i.e. a document on which you can for example use xf:setvalue.

<xf:action ev:event="xforms-submit-serialize">
<!-- Get initial document to submit -->
<xf:var
name="request-document"
value="xxf:mutable-document(saxon:parse(/my/request))"/>
<!-- Set value -->
<xf:setvalue
ref="$request-document/my/first-name">Joe</xf:setvalue>
<!-- Serialize request document -->
<xf:setvalue
ref="event('submission-body')"
value="saxon:serialize($request-document, instance('my-output-instance'))"/>
</xf:action>

Note that by compatibility with the XSLT document() and XPath 2.0 doc() functions, and unlike the instance() function, xxf:mutable-document() returns a document node, not a document element.

xxf:serialize()

xxf:serialize(
$item as node(),
$format as xs:string?
) as xs:string

The xxf:serialize() function allows you to serialize an XML node to XML, HTML, XHTML or text. For example:

<xf:bind ref="my-html" calculate="xxf:serialize(instance('my-instance'), 'html')"="">

xxf:sort()

xxf:sort(
$sequence as item()*,
$sort-key as item(),
$datatype as xs:string?,
$order as xs:string?,
$case-order as xs:string?
) as item()*

Note that the second argument differs from the exf:sort() function: it does not take a plain string but a literal expression, for example:

<xf:itemset
ref="
xxf:sort(
instance('samples-instance')/file,
@name,
'text',
'ascending'
)">
...
</xf:itemset>