Re: XML Schema for XTM DTD

Hi Max,

This began in topicmapmail and I am sending the reply to one mail list only 
to avoid cross posts and continue the thread in topicmapmail.


*Max Voskob wrote:
> Could anyone prove that I'm wrong in my supposition that XTM cannot be
> legitimately extended thru elements and attributes from other namespaces?
> Lets say that I want to add a couple more attributes from another namespace
> to instanceOf element. I can't see any way how it can be done at the moment.
>
> Is there actually a namespace identifier for the current version of XTM?

*M Nishikawa

 http://www.topicmaps.org/xtm/1.0/   Should be this, no?

I'm pretty sure that you can import attributes from any namespace, but this 
would mean your xml would not conform to the  XTM dtd. For example, all of 
the xlink attributes are not usable in XTM, but you can import them in anyway.

I think that Murray said something to this effect earlier in a related 
thread. http://www.infoloom.com/pipermail/topicmapmail/2003q1/004343.html
Please take a look at related posts from Murray.

*Alexander Johannesen
> You could be tempted to use the xlink:role for an XPath expression
 > in combination with the xlink:href, but XTM doesn't support this
 > subset of XLink, and the XLink didn't really have this use in mind,
 > but it is a CDATA field with that *possibility*.

*Murray Altheim
It's not quite as simple as that. I was the one who did the initial
design of the XLink part of XTM, and I read very carefully over the
XLink spec and had a number of discussions, both in person and in
email with various people on the W3C linking WG, including Eve Maler.
The problem is that in XLink, linking structures can't be deep; the
relationship between linking components in XLink can only be direct
children of their parent links, not deeper. There was no way to use
an extended linking structure in XTM unless XTM had no significant
linking structures deeper than direct parent-child elements, and so
we in the end were forced to use simple XLinks, which means we lost
about 90% of the cool stuff in XLink. For more info, see

     http://www.w3.org/TR/xlink/#extended-link
     http://www.w3.org/TR/xlink/#simple-links


*M Nishikawa
Extending the XTM would be something else altogether, and the xml created 
would not be interchangeable with XTM syntax topic maps, but interesting, 
nevertheless. I would like to hear the reasons for doing this though. I am 
all ears :)

Cheers,
Mary


> > At 13:22 2003/02/02 +0100, Steve Pepper wrote:
> > >It is way past time we did an XML Schema for the XTM DTD.
> > >
> > >Thanks for raising this issue, Max, and thanks for chiming in, Daniel!
> > >
> > >As I understand, both Max and Daniel have created their own XSD versions
> > >of the XTM DTD. Would there be any chance of the two of you getting
> together
> > >to compare notes and come up with a definitive version? If so, that would
> be
> > >of great help to the committee.
> >
> > Yes, Steve, I have  a version too :)
> >
> > Max, thanks for sending yours to the list. XML Spy is a great tool, isn't
> it :)
> > Our versions are a little different though and it would be good to compare
> > them. I did mine last year and included the psi for languages and the
> > standard PSIs that came with the xtm.dtd (pre ISO annex). I would need to
> > take these out, I think.
> >
> > It would be good to compare these with Daniel's, if he would like to
> > participate,  come up with a draft  and have it reviewed, and tested. I
> > think that there are various ways to approach writing the schema as Murray
> > mentioned, but that doesn't mean that an informative version can't be
> > published. As long as the xml that is created is consistent with the xml
> > that is created from the  DTD, it should be fine.
> >
> > There are just some tools that need the XSD, and it would be a good thing
> > to provide it.
> >
> >  From the reply that I have received from the UDDI Committee, it may not
> be
> > something they need now, but others will request it too, and it would be
> > good to have one "version."
> >
> >
> <http://lists.oasis-open.org/archives/uddi-spec-comment/200301/msg00003.html>http://lists.oasis-open.org/archives/uddi-spec-comment/200301/msg00003.html
> >
> >
> http://lists.oasis-open.org/archives/uddi-spec-comment/200301/msg00004.html
> >
> >
> > >*Steve P.
> > >If you could then submit it, I will do what I can (with Mary's help!) to
> > >ensure that it gets the ISO stamp of approval as soon as possible.
> >
> > Thanks Steve!
> >
> > Cheers,
> > Mary
> >
> >