Document versioning and XML Schema

[Brian Major]

Thanks for the responses Markus and Norman.  I have to agree: we need a
better way to allow schema/syntax changes.  A good first step would be to
remove the specification version number from the namespaces in the schemas,
but this should probably be discussed with the wider IVOA community.  Then
perhaps we can talk about options such as the approach taken by Schematron.
 A discussion item for Banff?

Unless there are objections (especially from VOSpace implementors), I plan,
in the next few weeks, making available for review a VOSpace 2.1 WD that
has minor XML schema changes.  I don't see the proposed changes adding any
considerable work to update existing v2.0 implementations.  Clients and
servers would have to allow for these new optional elements but aren't
required to act upon them.

Cheers,
Brian

On Mon, Jun 23, 2014 at 3:04 AM, Norman Gray <norman at astro.gla.ac.uk> wrote:

>
> Greetings.
>
> On 2014 Jun 23, at 10:21, Markus Demleitner <
> msdemlei at ari.uni-heidelberg.de> wrote:
>
> > My impression is that most clients already try some sort of "best
> > effort"-parsing (extracting what they think they understand,
> > discarding what they don't, and freely interpolating otherwise).
>
> For what it's worth, I think this is a better (that is, more realistic,
> and more robust) approach than compulsively validating against an XSchema.
>
> This is the general approach of Schematron[1], which is duck-typing for
> XML, without the heuristic vagueness which the term 'duck-typing' usually
> suggests.
>
> > I think we'd have a much better VO if they didn't have to work
> > *against* our standards and practices to do this -- and adopting a
> > model where the semantics of this best effort are rigorously defined
> > would also let us evolve certain aspects of our standards much more
> > smoothly.
>
> It is my firm belief that the IVOA's early adoption of XSchema contributed
> to a fixation on syntax, at the expense, sometimes, of the shared semantics
> that is surely the real goal of the IVOA.
>
> All the best,
>
> Norman
>
>
> [1] See <http://www.schematron.com/>, with a compact overview at <
> http://www.schematron.com/overview.html>.
>
> --
> Norman Gray  :  http://nxg.me.uk
> SUPA School of Physics and Astronomy, University of Glasgow, UK
>
>


-- 
Brian Major

Canadian Astronomy Data Centre
Centre canadien de données astronomiques

National Research Council Canada
Conseil national de recherches Canada
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