Used within xsl:merge-action, this returns the value that is the merge key of the items being
processed by this activation of
current-merge-key() ➔ xs:anyAtomicType*
There are no arguments
Links to W3C specifications
Available in XSLT 3.0. From Saxon 9.8, available in all editions.
Notes on the Saxon implementation
Introduced in Saxon 9.6; previously
current-grouping-key() was overloaded
for this purpose.