[XML-SIG] XBEL documentation, draft

Greg Stein gstein@lyra.org
Thu, 08 Oct 1998 15:15:37 -0700

Fred L. Drake wrote:
>   I have a draft copy of the XBEL documentation.  It's available at:
>         http://www.python.org/sigs/xml-sig/xbel/doc/
>   It is incomplete, but I am interested in comments.  I've attached
> the current DTD below; the only change is that <info> now requires at
> least one <metadata>.  Software that removes the last <metadata>
> should discard the <info> as well.
>   I don't recall that we reached resolution on the metadata stuff;
> I'll leave it alone unless issues are brought up at this point.
>   We also haven't reached a conclusion regarding the use of parameter
> entities to make the DTD more easily extended; are there any remaining
> issues there?  My inclination is to "do it right" to allow DTD reuse,
> but there were sentiments that went the other way.

The DTD wasn't attached :-)

Nevertheless, I feel that the metadata element has very little purpose.
Given the presence of XML Namespaces
(http://www.w3.org/TR/WD-xml-names), I don't think that the metadata tag
adds any value. Rather than use <metadata owner="http://foo.com/app">,
we can use <app:mytag xmlns:app="http://foo.com/app">. Of course, there
are other ways to specify the use of a namespace, but the point is that
a "metadata-like" facility has already been defined in a standardized
fashion (with the caveat of minor perturbations to the working draft
prior to IETF acceptance).

<info> still adds some value, in that the spec can say "app-specific
extensions should go into the <info> element; any application should
retain all child elements of the <info> element when manipulating items
in the XBEL document."

%common.attrs% is not very useful as an extension. It is located to
broadly for somebody to extend the DTD. If you try to add something into
%common.attr% it shows up EVERYWHERE. eek. Personally, I'm of the mind
that somebody can issue a second version of the DTD, rather than attempt
to extend it. At the present time, I'm not aware of apps that actually
make use of extending a DTD. Why should we make an attempt which might
not even be in the right direction? I'd say: let some precedent exist
before biting this off.

Further, given the presence of XML namespaces, an XBEL document can
simply be incorporated *within* another XML document. i.e. extension via
containment, rather than extension via derivation.

The simplest designs always seem to be the most used designs, in my
book. :-)  (and I'm a big fan of KISS)


Greg Stein (gstein@lyra.org)