XSL query inner xml - xslt

Question

Say this is my xml :
<History>
<University>TSU</University>
<Payload>
<Attrib Order="0">OVERSEA</Attrib>
<Attrib Order="1">GRADE2</Attrib>
<Attrib Order="2"><Person><ID>TQR344</ID></Person></Attrib>
<Attrib Order="3">3566644</Attrib>
</Payload>
</History>
And I want to query the inner XML inside Order=2 tag and read ID of the person.
I have created this so far :
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
>
<xsl:output method="xml" encoding="UTF-8" indent="yes" omit-xml-declaration="no" />
<xsl:template match="/History">
<xsl:apply-templates select="/History" />
</xsl:template>
<xsl:template name="Person" match="//History">
<Event>
<Uni><xsl:value-of select="University" /></Uni>
<ID><xsl:value-of select="Payload/Attrib[#Order='2']/Person/ID" disable-output-escaping="yes" /></ID>
</Event>
</xsl:template>
</xsl:stylesheet>
But as you can see it is not working.
Also I assigned the inner XML into a variable and tried to query that variable and It didn't work too.
Is it possible to do that via xsl ?
Limitations : I cannot change xml format. But maybe I was able to move from xsl ver 1 to new versions.

Answer 1

I want to query the inner XML inside Order=2 tag
The tag in question does not contain any XML; its content is a string and needs to be manipulated using string functions. Try:
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="utf-8" indent="yes"/>
<xsl:template match="/History">
<Event>
<Uni>
<xsl:value-of select="University" />
</Uni>
<ID>
<xsl:value-of select="substring-before(substring-after(Payload/Attrib[#Order='2'], '<ID>'),'</ID><')"/>
</ID>
</Event>
</xsl:template>
</xsl:stylesheet>
Note:
1. This:
<xsl:template match="/History">
<xsl:apply-templates select="/History" />
</xsl:template>
creates an infinite loop and will crash your processor.
2. Alternatively, you could serialize the string back into XML and process the result as XML; in XSLT 1.0, this can be done only by outputting the string with the escaping disabled, saving the result as a new document, then processing the new document with another XSLT stylesheet. Using XSLT 3.0 (or a processor that supports serializing as an extension) this can be all done during the same transformation.