Hi Martynas,
as I stated earlier, this was rather due to laziness and trying to
play safe as I didn't want to spend the time to enumerate all
possible "valid" SPIN RDF properties that could have shown up. This
is certainly doable though, and a simple solution may be to allow
everything outside of SP, SPL, SPIN namespaces.
If this is an issue that affects you, we now have a better solution
to accept user contributions. I have basically stopped working on
the SPIN API as a separately hosted entity, and the code base now
lives on GitHub as part of the SHACL API:
https://github.com/TopQuadrant/shacl
My working process is that I am first applying and testing changes
to SPIN or SHACL in our private TopBraid repo. From time to time I
copy those changes over to the public repo above. We could now also
go in the reverse direction. If someone has a patch to contribute
then I would accept them into the public and (from there) into the
TopBraid repo. It would be great if you could test a suitable fix
for "my" code and send me a patch, e.g. as a pull request.
Thanks
Holger