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Re: More proposals -- and some critical implementation issues



At 10:06 AM 1/2/97, Joe English wrote:
>It was not my impression that one of the goals of XML
>was to eliminate DTDs altogether; I thought we were
>only trying to enable "naked parsing".

Well, I didn't mean eliminate them for all purposes, but certainly I think
an application like MSIE or Navigator should be able to work without a DTD.
And that means that linking can't depend on the DTD.

>"Naked processing"
>is a different matter -- it seems pretty clear to me that
>some applications are going to need to parse (at least part of)
>the DTD in any case, e.g., in order to process external
>entity references.

And so I think we can't satisfy the goals of naked parsing (easy
implementation of simple processing) unless we can implement naked
processing (at least for documents with links and a stylesheet). So we _do_
need naked processing. I have always assumed that many external entity
references would live in the DTD subset for exactly this reason. Did I miss
something so that this doesn't work?

>I don't see how parsing <!ATTLIST ...> declarations
>is any harder than parsing "the stylesheet" -- depending
>of course on what notation we end up using for "the
>stylesheet", but if it's DSSSL I'd guess that implementors
>would have an easier time with a DTD.

It's the dowloading of DTDs that people have objected to, not the parsing,
per se, although skipping the DTD parser does simplify things by a
detectable amount.

> If bullet-biting
>looks inevitable, I suggest that we should use SGML's
>constructs for associating information with element types
>(#FIXED attributes) over other, as-yet undefined solutions
>(embedded stylesheets).

   After thinking through the implications of HTTP 1.1's persistent
connections I think we may be able to live without biting any bullets at
all. I must say that it's going to be hard to fit a whole DSSSL stylesheet
into #FIXED attributes.

   But I agree that this is the best bet for declaring link semantics in
the DTD. And stylesheets that can guess these values (say from the element
name) need not access DTDs to find their values.

   -- David

I am not a number. I am an undefined character.
_________________________________________
David Durand              dgd@cs.bu.edu  \  david@dynamicDiagrams.com
Boston University Computer Science        \  Sr. Analyst
http://www.cs.bu.edu/students/grads/dgd/   \  Dynamic Diagrams
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