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Re: XML and EDI

From: <lee@sq.com>
Date: Thu, 5 Jun 97 12:35:10 EDT
Message-Id: <9706051635.AA14556@sqrex.sq.com>
To: w3c-sgml-wg@w3.org
Steven R. Newcomb <srn@techno.com> wrote:
> XML really, really needs notation data attributes.  Without them, you
> can't do object inheritance from architecture (DTD) to architecture

I would humbly submit that this is nonsense :-)
I can conceive of a world in which object inheritance is performed without
SGML notation data attributes, and I have no difficulty in doing so.

> It's a small thing, really, but, wow, what a difference it makes!
I think you need to give some more concrete examples than "wow" :-), and
to explain exactly why this cannot be done with CDATA attributes or
with processing instructions or in some other way.

> The usefulness of inheritance for all kinds of purposes (and not least
> for EDI) is too great to ignore; it is one of the most useful and
> attractive aspects of SGML.
Well, that's very subjective.  I for one would strongly disagree.  I'd
happily get by without them.  In fact, I generally do.  So do most of
our customers.

Remember, we are not going for the high-end complex SGML applications here.
We are going for pervasive, easy to implement, easy to understand and
easy to describe.

> There is no good reason not to do it in XML.
It makes the specification longer.  It adds cost and complexity to
implementations.  It brings with it a whole new set of convepts to explain
and understand.  And it is, as far as I can tell, totally unnecessary.
There is no reason _to_ implement notation data attributes.

If SGML had been designed so that when I say
    <image format="GIF" encoding="base64">xxxxxx</image>
the xxxxxx woud be handled externally without going through the parser,
so that embedded &amp; or </ wouldn't cause a syntax error, the ability
to include inline notations would probably be more useful.

As it is, since the content will be treated as PCDATA, you do not gain
anything by using an attribute whose value is a notation name.
Furthermore, there is no way to enforce or chek this without a DTD.

> For a discussion of why architectural inheritability is overwhelmingly
> important, you may want to read my (now slightly dated) paper, "SGML
> Architectures: Implications and Opportunities for Industry" at
> http://www.techno.com/sgmlarchitecture.html.

This paper does not mention using notation data attributes -- it says
that CDATA attributes should be used.  I agree with it.

Lee
Received on Thursday, 5 June 1997 12:35:21 EDT

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