XSLT change from elements to attribute format - xslt

Question

What would be the XSLT to change this XML
<?xml version="1.0" encoding="utf-8"?>
<cas:ADDRESS_DETAILS PRIMARY_ADDRESS_INDICATOR="1" ADDRESS_ID="-289495914026885120" ADDRESS_TYPE="45001" ADDRESS_ACTIVE_FROM_DATE="2006-12-23" PERSON_ID="14512823342202880">
<cas:ADDRESS_ELEMENT VALUE="McMurchy Avenue" TYPE="ADD2" />
<cas:ADDRESS_ELEMENT VALUE="ON" TYPE="PROV" />
<cas:ADDRESS_ELEMENT VALUE="CA" TYPE="COUNTRY" />
<cas:ADDRESS_ELEMENT VALUE="Brampton" TYPE="CITY" />
<cas:ADDRESS_ELEMENT VALUE="440" TYPE="ADD1" />
</cas:ADDRESS_DETAILS>
In to this format
<?xml version="1.0" encoding="utf-8"?>
<cas:ADDRESS_DETAILS PRIMARY_ADDRESS_INDICATOR="1" ADDRESS_ID="-289495914026885120" ADDRESS_TYPE="45001" ADDRESS_ACTIVE_FROM_DATE="2006-12-23" PERSON_ID="14512823342202880" ADD2 ="McMurchy" PROV="ON" COUNTRY="CA" CITY="Brampton" ADD1="440">
</cas:ADDRESS_DETAILS>

Answer 1

Assuming you want to merge all ADDRESS_ELEMENTs inside their parent you can use
<xsl:template match="ADDRESS_ELEMENT[1]">
<xsl:copy>
<xsl:apply-templates select="../ADDRESS_ELEMENT" mode="to-attribute"/>
</xsl:copy>
</xsl:template>
<xsl:template match="ADDRESS_ELEMENT[position() > 1]"/>
<xsl:template match="ADDRESS_ELEMENT" mode="to-attribute">
<xsl:attribute name="{#TYPE}" select="#VALUE"/>
</xsl:template>
plus the identity transformation to handle the rest (i.e. <xsl:mode on-no-match="shallow-copy"/> in XSLT 3 (https://xsltfiddle.liberty-development.net/6qM2e2q) or the corresponding template in earlier versions)
If you want to transform the child elements into attributes of the parent, as your edit seems to indicate, you can simplify the code. Using a namespace requires some adaption however:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xpath-default-namespace="http://example.com/cas"
version="3.0">
<xsl:strip-space elements="*"/>
<xsl:output indent="yes"/>
<xsl:mode on-no-match="shallow-copy"/>
<xsl:template match="ADDRESS_DETAILS">
<xsl:copy>
<xsl:apply-templates select="#*, ADDRESS_ELEMENT"/>
</xsl:copy>
</xsl:template>
<xsl:template match="ADDRESS_ELEMENT">
<xsl:attribute name="{#TYPE}" select="#VALUE"/>
</xsl:template>
</xsl:stylesheet>
https://xsltfiddle.liberty-development.net/6qM2e2q/2