DevGuru XSLT function-available function

XSLT FUNCTION: function-available

Boolean = function-available(function-name)

The function-available function is used to test whether the function specified in the argument is supported by the XSLT processor. Currently, this is important when dealing with proprietary functions. In the future, this function will gain additional importance when you have to content with more than one version of the W3C XSLT standard.

If the function is supported, true is returned. If the function is not supported, false is returned.

The following XSLT and XPath functions should return true if a processor supports the W3C XSLT standard.

boolean	name
ceiling	namespace-uri
concat	normalize-space
contains	not
count	number
current	position
document	round
element-available	starts-with
false	string
floor	string-length
format-number	substring
function-available	substring-after
generate-id	substring-before
id	sum
key	system-property
lang	translate
last	true
local-name	unparsed-entity-uri

function-name

The function-name argument is simply the qname of the function that you wish to test. A qname is an XML name with an optional prefix. If the value is not of type string, it will automatically be converted to a string by the XPath string() function.

We use the DevGuru Staff List XML file for our example with the following header:
<?xml-stylesheet type="text/xsl" href="xslt_example_functionavailable.xsl"?>
and we name it: xslt_example_functionavailable.xml

We test to see if the aardvark function is available.

Code for xslt_example_functionavailable.xsl:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:template match="/">
<html>
<body>
<xsl:choose>
<xsl:when test="function-available('aardvark')">
<xsl:text>The aardvark function is available</xsl:text>
</xsl:when>
<xsl:otherwise>
<xsl:text>The aardvark function is not available</xsl:text>
</xsl:otherwise>
</xsl:choose>
</body>
</html>
</xsl:template>
</xsl:stylesheet>

Output:

Click to view output in separate window.