Core functions

Last updated 9 months ago

xxf:document-id()

xxf:document-id() as xs:string`

Each time an XForms document is created, typically when a user requests a page, it is assigned a unique id.

This function returns the current XForms document (or page)'s unique id.

xxf:evaluate-avt()

xxf:evaluate-avt(
$avt-expression as xs:string
) as item()*

This function is similar to saxon:evaluate() or xxf:evaluate(), but instead of evaluating an XPath expression, it evaluates a string representing an attribute value template.

<xf:output
value="
xxf:evaluate-avt(
'/xforms-sandbox/service/zip-zips?state-abbreviation={state}&amp;city={city}'
)"/>

xxf:format-message()

xxf:format-message(
$template as xs:string,
$params as item()*
) as xs:string

The xxf:format-message() function allows you to format a localized message based on a template and parameters.

  • the first parameter is a template string following the syntax of the Java MessageFormat class

  • the second parameter is a sequence of parameters that can be referenced from the template string

The following types are supported:

  • string (the default)

  • number (including currency and percent)

  • date

  • time

The function uses the current language as would be obtained by the xxf:lang() function to determine a locale.

Example with number, date, time, and string:

<xf:output
value="
xxf:format-message(
'At {2,time,short} on {2,date,long}, we detected {1,number,integer} spaceships on the planet {0}.',
(
'Mars',
3,
xs:dateTime('2010-07-23T19:25:13-07:00')
)
)"/>

This produces the following output with an en-US locale:

At 7:25 PM on July 23, 2010, we detected 3 spaceships on the planet Mars.

Example including a choice:

<xf:output
value="
xxf:format-message(
'There {0,choice,0#are no files|1#is one file|1&lt;are {0,number,integer} files}.',
xs:integer(.)
)"/>

This produces the following outputs, depending on the value provided:

There are no files.
There is one file.
There are 1,273 files.

NOTE: It is important to pass dates and times as typed values. Use xs:dateTime(), xs:date(), or xs:time() if needed to convert from a string.

xxf:lang()

xxf:lang() as xs:string?

The xxf:lang() function returns the current language as specified with the xml:lang attribute.

The xml:lang value to use is determined this way:

  • if the element containing the xxf:lang() function has an xml:lang attribute, that attribute is used

  • otherwise, the first ancestor element of the element containing the xxf:lang() function that has an xml:lang attribute is used

xml:lang is supported in the following locations:

  • for a static xml:lang value

    • on any XForms element

    • on the top-level <xh:html> element

  • for a dynamic xml:lang value (using an AVT)

    • only on the top-level <xh:html> element

NOTE: xml:lang attributes on HTML elements other than the top-level <xh:html> are ignored for the purpose of the xxf:lang() function.

NOTE: Format of the locale is currently restricted to the form "en" or "en-GB". Support for BCP 47 would be desirable.

Example of static values:

<xf:group xml:lang="it">
<!-- This output produces the value "it" -->
<xf:output value="xxf:lang()"/>
<!-- This output produces the value "zh" -->
<xf:output value="xxf:lang()" xml:lang="zh"/>
</xf:group>

Example with an AVT:

<xh:html xml:lang="{instance()}">
<xh:head>
<xf:model id="model">
<xf:instance id="instance">
<lang>it</lang>
</xf:instance>
</xf:model>
</xh:head>
<xh:body>
<xf:group>
<!-- This output produces "it" based on the top-level AVT, which
contains the value stored in the instance -->
<xf:output value="xxf:lang()"/>
<!-- This output produces "zh" -->
<xf:output value="xxf:lang()" xml:lang="zh"/>
</xf:group>
</xh:body>
</xh:html>

When calling the xxf:lang() function from an XBL component:

  • xml:lang is first searched as described above

  • if no xml:lang value is found in the XBL component, then the xml:lang value of the XBL bound element is searched

Example:

<xbl:xbl>
<xbl:binding id="fr-foo" element="fr|foo">
<xbl:template>
<xf:group>
<!-- The xml:lang value of the bound element is used -->
<xf:output value="xxf:lang()"/>
<!-- The xml:lang value is "zh" -->
<xf:output value="xxf:lang()" xml:lang="zh"/>
</xf:group>
</xbl:template>
</xbl:binding>
</xbl:xbl>

xxf:process-template()

[SINCE Orbeon Forms 2018.1]

xxf:process-template(
$template as xs:string,
$lang as xs:string,
$params as map(*)
) as xs:string?

This function fills a string template with values passed separately.

  • $template: template of the form:

    My name is {$name}. I am {$age} year-old.
  • $lang: language for formatting of parameters

  • $params: name → value XPath map

Example with xmlns:map="http://www.w3.org/2005/xpath-functions/map" in scope:

xxf:process-template(
'My name is {$name}. I am {$age} year-old. I own $ {$amount}.',
'en',
map:merge(
(
map:entry('name', 'Marco Polo'),
map:entry('age', 42),
map:entry('amount', 12.99)
)
)
)

This evaluates to:

My name is Marco Polo. I am 42 year-old. I own $ 12.99.

NOTE: As Orbeon Forms 2018.1, parameters are formatted per Java's MessageFormat. It is expected that in the future, these values will be formatted as they are with xf:output, and possibly configurable. If the exact format is important, instead of passing xs:integer, xs:date, etc. types, format the value as an xs:string first before passing it as parameter.

xxf:property()

xxf:property($property-name as xs:string) as xs:anyAtomicType?

The xxf:property() function retrieves the value of a property defined in properties-local.xml.

This function returns the following:

  • empty sequence if the property is not found

  • xs:string, xs:integer, xs:boolean or xs:anyURI depending on the actual type of the property

<xf:setvalue ref="my-property" value="xxf:property('my.property.name')"/>

xxf:r()

The purpose of this function is to automatically resolve resources by name given the current language and an XForms instance containing localized resources.

xxf:r($resource-name as xs:string) as xs:string?
xxf:r($resource-name as xs:string, $instance-name as xs:string) as xs:string?
  • $resource-name: resource path of the form foo.bar.baz. The path is relative to the resource element corresponding to the current language in the resources instance.

  • $instance-name: name of the resources instance. If omitted, search orbeon-resources and then fr-form-resources.

The function:

  • determines the current language based on xml:langattribute in scope where the function is in used

  • resolves the closest relevant resources instance

    • specified instance name if present

    • orbeon-resources or fr-form-resources (for Form Runner compatibility) if absent

  • uses the resource name specified to find a resource located in the resources instance, relative to the resource element with the matching language

Example:

<xf:instance id="orbeon-resources" xxf:readonly="true">
<resources>
<resource xml:lang="en"><buttons><download>Download</download></buttons></resource>
<resource xml:lang="fr"><buttons><download>Télécharger</download></buttons></resource>
</resources>
</xf:instance>
<xf:label value="xxf:r('buttons.download')"/>

[SINCE Orbeon Forms 2018.1]

The function supports filling a template with parameters when the $params is supplied:

xxf:r(
$resource-name as xs:string,
$instance-name as xs:string,
$params as map(*)
) as xs:string

In this case, the function fills the template as with the xxf:process-template() function.

xxf:resource-elements()

[SINCE Orbeon Forms 2018.2]

Like xxf:r(), The purpose of this function is to automatically resolve resources by name given the current language and an XForms instance containing localized resources. The difference is that this function resolves to resource elements instead of resolving to a resource string.

xxf:resource-elements(
$resource-name as xs:string
) as element()*
xxf:resource-elements(
$resource-name as xs:string,
$instance-name as xs:string
) as element()*
  • $resource-name: resource path of the form foo.bar.baz. The path is relative to the resource element corresponding to the current language in the resources instance.

  • $instance-name: name of the resources instance. If omitted, search fr-form-resources.

Example:

<xf:itemset ref="xxf:resource-elements('default-always-never.item')">
<xf:label ref="."/>
<xf:value ref="if (@id = 0) then 'default' else if (@id = 1) then 'true' else 'false'"/>
</xf:itemset>

xxf:rewrite-resource-uri()

xxf:rewrite-resource-uri($uri as xs:string) as xs:string

Rewrite a URI as an Orbeon Forms resource URI.