Re: Possible small RDDL enhancement

["Simon St.Laurent" <simonstl@simonstl.com>]

At 05:38 PM 3/19/01 -0500, Jonathan Borden wrote:
>It is interesting how the same issues and solutions keep popping up. I must
>admit that I totally missed this first (and second time around) -- of course
>I was expecting stuff to do with "processing" rather than defining what a
>namespace ought be, but of course as is often said: one person's processing
>is another person's data.

Yep.  I gave priority to the work parsers have to do, rather than the data 
they need to do it.  Since I'd always encountered these things as 
'processing problems'...

>XPDL does clearly lay the groundwork for 'document processing as a function
>of namespace dereferencing'
>http://www.simonstl.com/projects/xpdl/wd051000.html#Sec3.7 though as you
>note things like media-types (and for that matter notations) can be useful
>in some situations but are generally broken as a robust way to associate
>documents and processing. I think we can do better and agree with you below
>that this is good area to explore.

While I'm glad to have contributed to RFC 3023 - I think we improved XML 
MIME type usage substantially - I think we can do better with URIs than 
with MIME types in general, especially now that we have RDDL and related 
technologies to back them up.

>  The bottom line will be demonstrations
>and working implementations. I hope that people use RDDLClassLoader (java)
>but especially develop similar functionality for other languages.

Defnitely!  I'm also pushing on a RDDL-like approach to data typing as well 
as document typing; there seems to be some interest in the RELAX side of 
life, though I don't know that a change that substantial will happen at 
this point.

> > I'm also really intrigued by the possibility of interacting descriptions,
> > where it becomes possible to talk about multiple namespaces in a given
> > document in some coherent way.
>
>Something to mention is that 'xml:base' is very similar to 'rdf:about' in
>the sense that setting the xml:base of a rddl:resource sets -what- the
>rddl:resource is referencing. For example this might be a way to indicate
>that the document is intended to describe these namespaces:

Now if only I didn't consider xml:base an ugly interloper weakly tossed on 
top of XML 1.0, interfering with the infoset in especially weirdly 
complicated ways that require an understanding of which content is relative 
URIs...  I'll stick with absolute URIs, thanks.

> > I'm especially intrigued by the RELAX
> > 'divide-and-validate' bit:
> > http://www.xml.gr.jp/relax/divideAndValidate.html
> > http://xmlhack.com/read.php?item=1109
> >
> > I'm starting to think about programs that explore RDDL files over the
> > course of processing documents.  Could be some interesting possibilities
>there.
> >
>
>Leigh Dodds suggested the same thing for 'aggregating' Schematron schemata
>for RSS having multiply namespaced contents/modules.

It feels like a winning idea to me - I even hope W3C XML Schema 2.0 takes a 
serious look at such possibilities.

>This is along the theme of "schema at namespace URI" except that various
>schemata are thus *properties* of the namespace (which is a good thing IMHO)
>rather than a particular *equated* to the namespace (which would be a bad
>thing IMHO). In this model a namespace is indeed like a class whose
>properties are the resources the RDDL document contains.

And the RDDL document can define which properties that class has.  That's 
some pretty amazing stuff you cooked up there!



Simon St.Laurent - Associate Editor, O'Reilly and Associates
XML Elements of Style / XML: A Primer, 2nd Ed.
XHTML: Migrating Toward XML
http://www.simonstl.com - XML essays and books