format-dateTime

format-dateTime($value as xs:dateTime?, $picture as xs:string) → xs:string?

format-dateTime($value as xs:dateTime?, $picture as xs:string, $language as xs:string?, $calendar as xs:string?, $place as xs:string?) → xs:string?

Links to W3C specifications

Namespace: http://www.w3.org/2005/xpath-functions

Applies to: XPath 2.0, XSLT 2.0, XQuery 1.0 and later versions

XPath 2.0 Functions and Operators

XPath 3.0 Functions and Operators

Notes on the Saxon implementation

Formats a date, using a format controlled by the picture string. If no language is specified, the value is taken from the current Java locale. If the language (explicitly supplied or defaulted) is other than "en", the system tries to locate a localization class for the language (called, for historic reasons, a Numberer; this class must provide methods to perform the localization.

Support for English (language="en") is built-in in all versions of the product.

In Saxon-PE and Saxon-EE, support for a variety of other European languages is also built in: specifically da, de, fr, fr_BE, he, it, nl, nl_BE, and sv. The localization modules for these languages have names such as net.sf.saxon.option.local.Numberer_da. These modules are not built in with Saxon-HE, but they are available as open source code, and it is possible to configure them by writing a subclass of LocalizerFactory and registering it with the Configuration.

Localization modules for other languages can be configured. They are written to implement the interface Numberer, typically as subclasses of AbstractNumberer. In Saxon-HE they are configured in the same way as the system-supplied languages. In Saxon-PE and Saxon-EE they can be registered in one of two ways: programmatically using the call Configuration.getLocalizerFactory().setLanguageProperties("ja", props)) where props is a Properties object in which the class property is set to the name of the relevant Numberer class; or by setting an entry in the configuration file. For more information on writing localization modules, see Localizing numbers and dates.

If a calendar other than AD or ISO is specified, the result is prefixed "[Calendar: AD]" and is otherwise output as if the default calendar were used.

The country argument is currently used only when the format requests output of timezones by name (using [ZN]): for example with language="en", country="gb" and a date that falls in British Summer Time, +01:00 is output as "BST". This is problematic, because the information is not really available: the data type maintains only a time zone offset, and different countries (time zones) use different names for the same offset, at different times of year. If the value is a date or dateTime, and if the country argument is supplied, Saxon uses the Java database of time zones and daylight savings time (summer time) changeover dates to work out the most likely timezone applicable to the date in question.

If the timezone is formatted as [ZN,6] (specifically, with a minumum length of 6 or more) then the Olsen timezone name is output (again, this requires the country to be supplied). The Olsen timezone name generally takes the form Continent/City, for example "Europe/London" or "America/Los_Angeles". If the date/time is in daylight savings time for that timezone, an asterisk is appended to the Olsen timezone name.

When formatting times in the 12-hour clock, with language="en", the abbreviations "a.m." and "p.m." are used. These can be shortened to "am" and "pm" by giving a maximum width of 2 ([PN,*-2]). The US convention of denoting noon as "pm" and midnight as "am" is followed, unless the maximum width is 8 or more ([PN,*-8]) in which case these values are represented as "noon" and "midnight" respectively.

The rules for formatting of timezones have been clarified and extended in the XPath 3.0 version of the specification. As of Saxon 9.4, these changes are not yet implemented.