DALI examples vocab

[Markus Demleitner]

Hi DAL,

On Thu, May 19, 2016 at 09:04:03AM -0700, Patrick Dowler wrote:
> The plan is to create an RDFa vocabulary and then specify the URI as
> an http URL where one can get the machine readable vocabulary
> document. I haven't around to that yet so the URI in the DALI document
> is the correct one for now. I also haven't thought about whether such
> a change in URI is acceptable in a 1.0 -> 1.1 update... we did agree
> that TAP could extend the vocabulary so the URI for a TAP-specific
> example would be different and maybe we should produce RDFa for the
> service-specific vocabularies only.
> 
> Thoughts?

Excuse me for quoting myself from my collection of DALI 1.1 gripes at
http://mail.ivoa.net/pipermail/dal/2016-May/007490.html:

  (d) Sect 2.3: I'm almost totally sure the DALI vocabulary URI should
  *not* be an ivoid.  Rather, it should be a normal IVOA vocabulary URL,
  as in Datalink (so, here, I'd say http://www.ivoa.net/rdf/examples).

  In particular, whatever the base URL ends up being, it should not
  include a fragment identifier, because RDFa IIRC says the fragment
  identifier is used to complete term URIs (so, we'd have
  ivo://ivoa.net/std/DALI#examples#capability; that might even work out,
  but it's certainly a pain).

-- meaning: if we keep things as they are, we'd have to introduce 

  examples#name
  examples#generic-parameter

etc. StandardKeys into the StandardsRegExt record for DALI 1.1, and
while that would not be a *terrible* pain, in addition to being odd,
it'd be contrary to what I hope will converge to become a standard in
this kind of vocabularies within the IVOA (a.k.a., the datalink
thing).

So, I'd stronly advocate fixing this in 1.1, perhaps noting the
erroneous URI in 1.0.  In contrast to what I said above, I'd probably
use http://www.ivoa.net/rdf/dali-examples rather than just "examples"
-- that particular word has turned out to be confusingly generic
before.  What's behind that URL would be maintained just as the
datalink vocabulary.

And no, I don't think we should have multiple vocabularies here
(e.g., TAP examples would use a different vocabulary URI).  "Simple"
for me essentially always means "no parsing, no managing URIs" -- and
why should we have multiple vocabularies, since it's "the IVOA" in
every case that'd control them?

Cheers,

       Markus