IRIs for enums in Ontology?

[hgoerzig]

In the ontology the contents of enumerations is presented using simple strings:
For NXsource/type it looks like this:
<rdf:first rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Synchrotron X-ray Source</rdf:first>

The problem is that "Synchrotron X-ray Source" has no IRI. This makes these entries unmappable to other ontologies and is a barrier for data integration.

An other exmaple is the class NXunit_cell:
It is not possible to map NXunit_cell/crystal_system "triclinic" to http://purl.obolibrary.org/obo/PROCO_0000128 "triclinic unit cell" in the "Process Chemistry Ontology".

For integration of the new NXxas application definition it would be necessary to express the edge and the element with an IRI in order to map it e.g. to the IXDB protal in Japan https://mdr.nims.go.jp/collections/a0f3fbf1-f94a-4be7-8a66-6b91a24f6b54 .
They are using the matvoc the Cu K-edge would be https://matvoc.nims.go.jp/wiki/Item:Q2516

Is it possible to provide IRIs to the contents of the enums?

[mkuehbach]

At least from a technical perspective, one possibility could be to add a "gupri" or "is_equivalent_to" or alike as an XML attribute to nx:enumerationType in nxdl.xsd line 1287ish
but additional changes in the NeXus documentation will also be required.