XForms function callsAdded by IBM on August 8, 2013 | Version 1 (Original)
|XFDL supports the use of XForms functions. These functions can be included in XPath expressions, and are only available when dealing with XForms-related processes.
The following functions use Boolean conditions.
The following functions deal with numbers.
The following functions deal with strings.
The following functions deal with dates and time.
The following functions set the node.
The following functions are utility functions:
XForms uses XPath to address data nodes in binds, to express constraints, and to specify calculations. Simple XPath expressions resemble file system and directory paths in appearance. However, instead of moving through files and folders, XPath expressions move through nodes in the XForms data model. For more information about XPath, see http://www.w3.org/TR/xpath.
Return types XForms functions can return the following data types:
- Boolean – a true or false value.
- string – a group of alphanumeric characters.
- number – a double precision number.
- nodeset – a set of nodes in the data model. The set may be empty, or it may contain or more nodes.
Empty return values Some functions will return the string "NaN" when they are unable to compute a real return value. NaN means "not a number", and generally indicates an empty nodeset.