Proposed process for DTDs in XML

[Simon St.Laurent]

It sounds like we have a lot of genuine interest in using XML syntax for DTDs.

I remain somewhat concerned that we are potentially duplicating the work of 
others, particularly XML-Data and RDF.  The narrowness of scope that Peter has 
suggested for this project, as well as Tim's suggestion that getting ideas on 
the table for the XML WG to examine is worthwhile, reassure me that the work 
done here has a significant chance to contribute to the XML community in both 
the short and the long term.

I'm willing to devote a considerable amount of time to this project.  I do 
have two books to write this summer and I'm moving in June, but I think I can 
work around those obligations.  Additional volunteers (in addition to 
contributors) may be needed as this project develops. Unless someone else 
would like the position, I'm willing to attempt to do as good a job as David 
Megginson did with SAX.

As for the project and the process, there are a number of things to work out, 
before we even get down to syntax.

- Name of Project: Peter has referred to the project as DTDXML; at one point 
Paul Prescod referred to this type of DTD with the identifer xdtd.  I avoided 
naming it it in my original proposal.  Suggestions?

- Scope of Project: Are the schemas defined by this project intended to map a 
subset of current XML practice?  No one seems interested in making parameter 
entities, for instance, a part of this project. I suggested in my original 
proposal that parameter entities might in fact be unnecessary in this type of 
project.  Tim also brought up the question of "obscure" attribute types. (Data 
typing in general is a key issue, but one I'd like to avoid for right now.) 
There are always the internal/external battles as well. We'll need to figure 
out exactly what parts of XML are worth including.  Eventually, it may prove 
possible to map everything, but I think we'll be better off starting with less 
and building a firm base.  We need to define an achievable set of goals early.

- Linking to XML Documents: Tim asked "How do we associate the new schemas 
with document instances?" Current XML DTD's are defined/linked with the 
DOCTYPE declaration.  The DTDs defined with this project probably need a 
mechanism that indicates the DTD type - if they aren't converted to normalized 
XML 1.0 DTDs before validation, of course.  I'm not certain this mechanism 
should be defined in this proposal - linking schemas (and other supporting 
materials, like stylesheets) to documents seems to need another standard that 
isn't directly bound to this one.  Still, this issue needs consideration.

- Namespaces: My proposal used elements created without namespaces.  It seems 
like namespaces would be useful and/or necessary here.  It would probably be 
smart to decide on this _after_ the project has a name.

- Relation to other standards: As I said above, I don't want to stomp on the 
feet of the people working on RDF and XML-Data.  I'd like to see this proposal 
grow cooperatively, with little conflict with other proposals.  I also think 
the syntax presented for DTDs should be formally expressed using the XML 1.0 
DTD syntax.  (If it can be described using RDF and XML-Data as well, so much 
the better.)

- Relation to XML-DEV: This forum is easily the best place to gather 
high-level feedback, but I'm not sure everyone here wants to read all the 
proceedings.  I feel strongly that this disussion will benefit by being 
public, and public-domain.  Would it be acceptable to use XML-DEV, and make 
sure that all discussion includes whatever namespace token we choose on the 
subject line?  That would make it easy for people to filter in or out what 
they want to read.  (I'm also aware that there are people paying by the byte 
out there - if necessary, we could move to another space.)

- Document Creation: We also need to decide how to create this document.  My 
original proposal (at http://members.aol.com/simonstl/xml/) has been chewed on 
fairly well.  It might still serve as a base (_minus_ all the specific syntax 
I proposed) for further development.  Do people want to proceed this way, or 
should we start from a clean outline?

There's a lot to do, but it's definitely exciting!

Simon St.Laurent
Dynamic HTML: A Primer / XML: A Primer / Cookies


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