Standard functions

XPath 2.0 functions

Standard documentation

These functions are documented in XQuery 1.0 and XPath 2.0 Functions and Operators (Second Edition).

Functions

Orbeon Forms supports the XPath functions from XQuery 1.0 and XPath 2.0 Functions and Operators (Second Edition).

Example of use:

string-join(('cat', 'dog', 'alligator'), ', ')

Namespaces:

• These functions are available in the default function namespace.

• These function are also available in the XPath functions namespace (http://www.w3.org/2005/xpath-functions), usually associated with the fn prefix.

This means that it is usually not necessary to declare a namespace for these functions, nor is it necessary to use a prefix in calls to these functions.

We recommend not prefixing calls to the standard XPath functions.

Constructors

Orbeon Forms supports the XPath constructors from XQuery 1.0 and XPath 2.0 Functions and Operators (Second Edition).

Example of use:

xs:dateTime('2016-01-11T12:00:00Z')

These constructors are in the http://www.w3.org/2001/XMLSchema namespace, usually associated with the xs prefix. This means that using a prefix is required.

XPath 3.0 functions

Math functions

[SINCE Orbeon Forms 2020.1]

This version doesn't yet support XPath 3.0, but it supports a subset of XPath 3.0 math functions. These functions are in the http://www.w3.org/2005/xpath-functions/math namespace, which maps to the math prefix:

• math:log()

• math:sin()

• math:cos()

• math:tan()

• math:asin()

• math:acos()

• math:atan()

• math:atan2()

• math:log()

• math:exp()

For more information, see Trigonometric and exponential functions.

environment-variable()

[SINCE Orbeon Forms 2020.1]

This function returns the value of the specified environment variable. Before using this function, you'll want to set the oxf.xpath.environment-variable.enabled property to true. If that property isn't set to true, or the variable isn't defined, or the Java security doesn't allow access to environment variables, then the function returns an empty sequence.

environment-variable('SERVICE_HOST')

XForms functions

Standard documentation

These functions are documented in XForms 2.0's XPath Expressions Module.

Namespaces

• These functions are available in the default function namespace.

• These function are also available in the XForms namespace (http://www.w3.org/2002/xforms), usually associated with the xf prefix.

This means that it is usually not necessary to declare a namespace for these functions in the form, nor is it necessary to use a prefix in calls to the core XPath functions:

valid(element)

For extra clarity, you can prefix calls to XForms functions. For example:

xf:valid(element)

XForms 2.0 functions

xf:bind()

[SINCE Orbeon Forms 4.5]

xf:bind($id as xs:string) as node()*

This function returns the sequence of nodes associated with the bind specified by the id parameter.

xf:valid()

[SINCE Orbeon Forms 4.3]

xf:valid() as xs:boolean
xf:valid($items as item()*) as xs:boolean
xf:valid($items as item()*, $relevant as xs:boolean) as xs:boolean
xf:valid($items as item()*, $relevant as xs:boolean, $recurse as xs:boolean) as xs:boolean

The valid() function returns the validity of XPath items, including instance data nodes.

Boolean functions

• xf:boolean-from-string()

• xf:is-card-number()

Number functions

• xf:count-non-empty()

• xf:index()

• xf:power()

• xf:random()

String functions

• xf:property()

  • This function supports extension property names in the http://orbeon.org/oxf/xml/xforms namespace (usually mapped to the xxf prefix). Any such property name will return the value of an XForms engine property. Example:

    <xf:output value="property('xxf:noscript')"/>

  • NOTE: The standard XForms function returns an XPath 1.0 string. The Orbeon Forms implementation returns the following:

    • empty sequence (if the property is not found)

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

• xf:digest()

• xf:hmac()

Date and time functions

NOTE: Prefer the XPath 2.0 date and time functions when possible.

• xf:local-date()

• xf:local-dateTime()

• xf:now()

• xf:days-from-date()

• xf:days-to-date()

• xf:seconds-from-dateTime()

  • available as xf:seconds-from-dateTime() only

• xf:seconds-to-dateTime()

• xf:seconds()

• xf:months()

Node-set functions

• xf:instance()

• xf:current()

• xf:context()

Object functions

• xf:event()

Unsupported and obsolete XForms 1.1 functions

The following functions from XForms 1.1 are obsolete:

• xf:adjust-dateTime-to-timezone()

  • use the XPath 2.0 Timezone Adjustment Functions on Dates and Time Values, which offer similar functionality
• xf:avg()

  • use the standard XPath 2.0 function instead (avg())

  • the XForms 1.1 version of this function is not implemented in Orbeon Forms

• xf:choose()

  • use the native XPath 2.0 if (...) then ... else ... construct instead

• xf:id()

  • use the native XPath 2.0 id() function instead
• xf:if()

  • available as xf:if() only

  • use the native XPath 2.0 if (...) then ... else ... construct instead

• xf:min(), xf:max()

  • use the standard XPath 2.0 functions instead (min() and max())

  • the XForms 1.1 versions of these functions are not implemented in Orbeon Forms

XSLT 2.0 functions

Namespaces

These functions are available in the default function namespace.

Example:

format-number(xs:integer(year), '0000')

Functions

The following functions from XSLT 2.0 and XPath 3 are available:

• format-dateTime() (external documentation)
• format-date() (external documentation)
• format-time() (external documentation)
• format-number() (external documentation)

NOTE: Orbeon Forms, as of version 2021.1, still uses XPath 2.0. Even so, the functions above are available.

For an example, see Converting a date/time to a named timezone.

eXforms functions

Namespaces

These functions are available in the http://www.exforms.org/exf/1-0 namespace, usually associated with the exf prefix.

Functions

eXForms was a suggested set of extensions to XForms 1.0, grouped into different modules.

Orbeon Forms supports the exf:mip module, which includes the following functions:

• exf:relevant()

• exf:readonly()

• exf:required()

NOTE: XPath 2.0-compatible versions of these functions will be available as part of XForms 2.0.

Orbeon Forms also supports the following from the sorting module:

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

Note that the second argument is interpreted as a string, unlike with xxf:sort():

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