Marc van Grootel bwaumg@urc.tue.nl
Sun, 04 Oct 1998 15:57:45 +0200

Greg Stein wrote:
> Complexity is generally the reciprocal of usefulness. Some of the
> complexity that is bulking it up (e.g. common.attrs) almost appears to
> be like peacock feathers. :-)  Keep it simple... people will use it.

Greg Stein wrote:
> I believe the whole %common.attrs thing is bogus. It appears its only
> purpose in the DTD is to make it more complicated. It doesn't define any
> common attributes, and I bet nobody can come up with one that is common
> across ALL elements in there (it HAS been applied to all elements, after
> all).

I agree on the common.attrs issue, and partly on the complexity issue.
common.attrs looks like a hook for future extension of the
DTD. However, I think that currently it is not needed, and because it
is attached to many elements could cause problems when it will
actually be used. 

Secondly, generally, parameter entities are used to make the DTD
clearer (more self documenting) not more complex. What kind of
complexity are we talking about here? The perceived complexity of a
DTD says little about the complexity of the average document

Maybe all the special entity sets can be left out. But what harm is
there in explicitly declaring those few entities (<,>,&,',") for
interoperability?  Even the spec suggests it.

Sean Mc Grath wrote:
> Looking to the future a bit:-
> <PossibleHeresyAlert>
> I can see the entire entity architecture of XML being depracated
> in favour of transclusion etc. via XLink.
> I can see DTDs becoming a "compatability only" way of doing schemas.
> 9 out of 10 XBEL aware apps will use non-validating XML parsing!
> </PossibleHeresyAlert>

Greg Stein wrote:
> Actually, this begs the whole question: what the heck are metadata
> elements doing in there anyhow? Why not use arbitrary XML elements (with
> their potential for a namespace)? Your example above looks suspiciously
> like namespaces. Here is an example:
> <?xml:namespace ns="http://www.lyra.org/greg/stuff" prefix="gjs" ?>
> <xbel>
> ..
>       <info>
>         <gjs:hello foo="bar"/>
>         <gjs:another />
>       </info>
> </xbel>
> I'd say punt the whole metadata thing and rely on applications to define
> their own XML elements and place those into the <info> area.

To me these are important points. I hate to let SGML compatibility and
the possibility of validating against a DTD go. Especially given the
status of XML namespaces versus SGML. Maybe I'm just having troubles
adapting to XML. It may not be heresy but after a while people may
indeed say "why the hell bother with DTD's they're a nuisance". At
that point others will start getting a severe case of deja-vu as they
remember what happened to HTML and nostalgically haul out a dusty
manual with that XML 1.0 specification where it says: "XML shall be
compatible with SGML" and "The number of optional features in XML is
to be kept to the absolute minimum, ideally zero". But that's just my

Marc van Grootel