XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition (571 page)

If the picture string is invalid, then the implementation is required to report an error.

Usage

Note that this facility for formatting numbers is completely separate from the facilities available through the

element. There is some overlapping functionality, but the syntax of the pictures is quite unrelated. The
format-number()
function formats a single number, which need not be an integer.

is primarily designed to format a list of positive integers. For formatting a single positive integer, either facility can be used.

Examples

The following example shows the result of
format-number()
using the default decimal format. Examples with non-default decimal formats are shown under the

element in Chapter 6, page 298.

See Also

page 298 in Chapter 6

page 403 in Chapter 6

format-time

See
format-date()
on page 781

function-available

This function is available in XSLT only
.

You can call
function-available()
to test whether a particular function is available for use. It can be used to test the availability both of standard system functions and of user-written functions, including both XSLT stylesheet functions and extension functions.

For example, the expression
function-available(‘concat’)
returns
true
.

Changes in 2.0

An optional second argument has been added, giving the arity of the required function.

In XSLT 2.0, except when running in backward-compatibility mode, it is a static error if an XPath expression contains a call on a function that is not available. Therefore, the way in which
function-available()
is used needs to change: instead of calling it using a normal runtime conditional instruction
(
or

), it should be called in a compile-time conditional expression, using the
[xsl:]use-when
attribute.

Signature

Effect

The first argument must take the form of a lexical
QName
: that is, an XML name, with an optional namespace prefix that corresponds to a namespace declaration that is in scope at the point in the stylesheet where the
function-available()
function is called.

If there is no prefix, or if the namespace URI is the standard function namespace
http://www.w3.org/2005/xpath-functions
, the call tests whether there is a system function with the specified name. The system functions are those defined in the XPath and XSLT Recommendations; vendors are not allowed to supply additional functions in this namespace, nor are they allowed to omit any. So an XSLT processor that conforms to XSLT version 2.0 will return
true
if the name is one of the function names in this chapter (for example
current
,
position
, or
regex-group
). This means you can test whether a new XPath 2.0 or XSLT 2.0 function is supported in your XSLT processor by writing, for example:

If the
QName
includes a non-null namespace (other than the standard function namespace), the XSLT processor returns
true
if there is a stylesheet function, constructor function, or extension function available with the given name. In general, if
function-available()
returns
false
, then you are safe in assuming that a call on the function would fail, and if it returns
true
, then there will be some way of calling the function successfully.

If the second argument to the function is supplied, then
function-available()
returns
true
only if there is a function available with the specified name and the specified number of arguments. When the second argument is omitted, the result is true if there is some function with the required name, regardless of the number of arguments.