Re: Make DTDs optional?

At 01:54 AM 10/1/96 +1000, Rick Jelliffe wrote:

>Is this really more what XML should be about: a markup language for
>presenting documents in the form required by the application?  (Which
>would correspond to the normalised form of an SGML document when parsed
>against archetectural forms that model the XML application.) In other
>words, a  temporary/application/closed-system format rather than a 
>archiving/modelling/manipulation/open-system format like SGML.  (no flames 
>about 'format' please) 

I've been staying quiet in this discussion group, but Rick's comment
provides me the opportunity for saying something I've been thinking
increasingly for about a week:

Are we trying to do here the thing that ODA *should have been*?

That is to say, is an XML document something that has structure, though
perhaps not the kind of structure most of us have put in traditional SGML
applications. There has been some discussion of deducing a DTD, using a tool
like FRED, but is even that what we need? 

Charles and I wasted plenty of time dealing with ODA, and I'd hate to
replicate that experience. But we did learn some things from it, like what
led to architectural forms. It would be a great mistake if, while trying to
simplify building applications on something that was related to SGML, we
wound up getting so convoluted as ODA became (so convoluted it was
unimplementable). However, their original idea was implicit logical
structures, things that could be drived from tracing levels of nesting. I
think that's what I'm hearing here.

I'm one of the folks who believes in mandatory DTDs, but that's because most
of the applications I deal with fall into what Rick calls a
"archiving/modelling/manipulation/open-system format". Maybe there is a
valid case for implicit structure in a "temporary/application/closed-system
format". If we go that route, we really do need to keep things simple and
avoid overspecifying.


Dr. James D. Mason
(ISO/IEC JTC1/SC18/WG8 Convenor)
Lockheed Martin Energy Systems
Information Management Services
SGML Systems Development
1060 Commerce Park, M.S. 6480
Oak Ridge, TN  37831-6480   U.S.A.
Telephone: +1 423 574-6973
Facsimile:  +1 423 574-0004
Network: masonjd@ornl.gov