The filename NXDL_VERSION is misleading

[woutdenolf]

Following this discussion: #1455

The NXDL version is the version of the language in which we write the NeXus definitions. This is currently 3.1:

definitions/nxdl.xsd

Line 5 in 583de13

xmlns:nx="http://definition.nexusformat.org/nxdl/3.1"

The NeXus version is the release version of the NeXus definitions. This currently v2024.02:

We have a file called NXDL_VERSION which contains the string "v2024.02":

definitions/NXDL_VERSION

Line 1 in 583de13

v2024.02

I propose to rename this file to "NEXUS_VERSION" in accordance or whatever we decide to use in #1455.

[woutdenolf]

Looking at the git tags, these are the latest NeXus versions

v2024.02
v2022.07
v2022.06
v3.3
v3.2
v3.1.0

So I suspect after 3.1 the NXDL version and the Nexus version were decoupled.

This issue notes that we don't have a way of releasing NXDL itself (i.e. the XSD files): #1031. We also don't seem to increment the version when adding changes.