XSLT generate UUID
Here's a good example. Basically you set up an extension that points to the java UUID class, and then reference it in the XSL:
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:uuid="java:java.util.UUID">
<xsl:template match="/">
<xsl:variable name="uid" select="uuid:randomUUID()"/>
<xsl:value-of select="$uid"/>
</xsl:template>
Here is the easiest and shortest way to do this in pure XPath 2 or higher:
unparsed-text("https://uuidgen.org/api/v/4")
If you want to generate many GUIDs, say 100, do this:
for $i in 1 to 100
return unparsed-text(concat("https://uuidgen.org/api/v/4?x=", $i))
Explanation:
Because the standard XSLT 2.0 / XPath 3.0 (and greater version) function unparsed-text() is deterministic it must return the same result on each invocation with the same argument. A compliant XPath implementation must thus cache the first response and only produce the cached response henceforth for the same argument.
To avoid this, we generate a slightly-different URL for each call, thus making the XPath specification authors' efforts futile.
Enjoy 
Since XSLT is a functional language, generating random numbers is not part of the language. That said, there are extension packages (EXSLT) and some processors (Saxon) that support generation of random numbers. If you can't use extensions or Saxon, then I believe you're out of luck.
You can use xslt snippet for this (source: http://code.google.com/p/public-contracts-ontology/source/browse/transformers/GB-notices/uuid.xslt?r=66e1d39a1c140079a86d219df5b3e031007cc957):
<xsl:stylesheet xmlns:uuid="http://www.uuid.org" xmlns:math="http://exslt.org/math" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
<xsl:template match="/">
<xsl:value-of select="
concat('First random ID:', uuid:get-id()),
concat('Base timestamp: ', uuid:generate-timestamp()),
concat('Clock id: ' ,uuid:generate-clock-id()),
concat('Network node: ' ,uuid:get-network-node()),
concat('UUID Version: ' ,uuid:get-uuid-version()),
concat('Generated UUID: ' ,uuid:get-uuid()),
concat('Generated UUID: ' ,uuid:get-uuid()),
concat('Generated UUID: ' ,uuid:get-uuid()),
concat('Generated UUID: ' ,uuid:get-uuid())
" separator=" "/>
</xsl:template>
<!--
Functions in the uuid: namespace are used to calculate a UUID
The method used is a derived timestamp method, which is explained
here: http://www.famkruithof.net/guid-uuid-timebased.html
and here: http://www.ietf.org/rfc/rfc4122.txt
-->
<!--
Returns the UUID
-->
<xsl:function name="uuid:get-uuid" as="xs:string*">
<xsl:variable name="ts" select="uuid:ts-to-hex(uuid:generate-timestamp())"/>
<xsl:value-of separator="-" select="
substring($ts, 8, 8),
substring($ts, 4, 4),
string-join((uuid:get-uuid-version(), substring($ts, 1, 3)), ''),
uuid:generate-clock-id(),
uuid:get-network-node()"/>
</xsl:function>
<!--
internal aux. fu
with saxon, this creates a more-unique result with
generate-id then when just using a variable containing a node
-->
<xsl:function name="uuid:_get-node">
<xsl:comment/>
</xsl:function>
<!-- generates some kind of unique id -->
<xsl:function name="uuid:get-id" as="xs:string">
<xsl:sequence select="generate-id(uuid:_get-node())"/>
</xsl:function>
<!--
should return the next nr in sequence, but this can't be done
in xslt. Instead, it returns a guaranteed unique number
-->
<xsl:function name="uuid:next-nr" as="xs:integer">
<xsl:variable name="node">
<xsl:comment/>
</xsl:variable>
<xsl:sequence select="
xs:integer(replace(
generate-id($node), '\D', ''))"/>
</xsl:function>
<!-- internal fu for returning hex digits only -->
<xsl:function name="uuid:_hex-only" as="xs:string">
<xsl:param name="string"/>
<xsl:param name="count"/>
<xsl:sequence select="
substring(replace(
$string, '[^0-9a-fA-F]', '')
, 1, $count)"/>
</xsl:function>
<!-- may as well be defined as returning the same seq each time -->
<xsl:variable name="_clock" select="uuid:get-id()"/>
<xsl:function name="uuid:generate-clock-id" as="xs:string">
<xsl:sequence select="uuid:_hex-only($_clock, 4)"/>
</xsl:function>
<!--
returns the network node, this one is 'random', but must
be the same within calls. The least-significant bit must be '1'
when it is not a real MAC address (in this case it is set to '1')
-->
<xsl:function name="uuid:get-network-node" as="xs:string">
<xsl:sequence select="uuid:_hex-only('09-17-3F-13-E4-C5', 12)"/>
</xsl:function>
<!-- returns version, for timestamp uuids, this is "1" -->
<xsl:function name="uuid:get-uuid-version" as="xs:string">
<xsl:sequence select="'1'"/>
</xsl:function>
<!--
Generates a timestamp of the amount of 100 nanosecond
intervals from 15 October 1582, in UTC time.
-->
<xsl:function name="uuid:generate-timestamp">
<!--
date calculation automatically goes
correct when you add the timezone information, in this
case that is UTC.
-->
<xsl:variable name="duration-from-1582" as="xs:dayTimeDuration">
<xsl:sequence select="
current-dateTime() -
xs:dateTime('1582-10-15T00:00:00.000Z')"/>
</xsl:variable>
<xsl:variable name="random-offset" as="xs:integer">
<xsl:sequence select="uuid:next-nr() mod 10000"/>
</xsl:variable>
<!-- do the math to get the 100 nano second intervals -->
<xsl:sequence select="
(days-from-duration($duration-from-1582) * 24 * 60 * 60 +
hours-from-duration($duration-from-1582) * 60 * 60 +
minutes-from-duration($duration-from-1582) * 60 +
seconds-from-duration($duration-from-1582)) * 1000
* 10000 + $random-offset"/>
</xsl:function>
<!-- simple non-generalized function to convert from timestamp to hex -->
<xsl:function name="uuid:ts-to-hex">
<xsl:param name="dec-val"/>
<xsl:value-of separator="" select="
for $i in 1 to 15
return (0 to 9, tokenize('A B C D E F', ' '))
[
$dec-val idiv
xs:integer(math:power(16, 15 - $i))
mod 16 + 1
]"/>
</xsl:function>
<xsl:function name="math:power">
<xsl:param name="base"/>
<xsl:param name="power"/>
<xsl:choose>
<xsl:when test="$power < 0 or contains(string($power), '.')">
<xsl:message terminate="yes">
The XSLT template math:power doesn't support negative or
fractional arguments.
</xsl:message>
<xsl:text>NaN</xsl:text>
</xsl:when>
<xsl:otherwise>
<xsl:call-template name="math:_power">
<xsl:with-param name="base" select="$base"/>
<xsl:with-param name="power" select="$power"/>
<xsl:with-param name="result" select="1"/>
</xsl:call-template>
</xsl:otherwise>
</xsl:choose>
</xsl:function>
<xsl:template name="math:_power">
<xsl:param name="base"/>
<xsl:param name="power"/>
<xsl:param name="result"/>
<xsl:choose>
<xsl:when test="$power = 0">
<xsl:value-of select="$result"/>
</xsl:when>
<xsl:otherwise>
<xsl:call-template name="math:_power">
<xsl:with-param name="base" select="$base"/>
<xsl:with-param name="power" select="$power - 1"/>
<xsl:with-param name="result" select="$result * $base"/>
</xsl:call-template>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>:choose>
</xsl:template>
</xsl:stylesheet>