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Re: 2.1 a-d: Link Recognition by Reserved Attribute?

From: Len Bullard <cbullard@hiwaay.net>
Date: Fri, 21 Feb 1997 17:17:15 -0600
Message-ID: <330E2CFB.D0B@hiwaay.net>
To: Michael Sperberg-McQueen <U35395@UICVM.UIC.EDU>
CC: W3C SGML Working Group <w3c-sgml-wg@w3.org>
Michael Sperberg-McQueen wrote:

> I think this discussion is beginning to show signs that the participants
> are missing some of each other's basic assumptions, though those
> assumptions seem clear enough to some of the rest of us.

Glad to know some of us read minds better than others.
 
> If I understand Len and others aright, they worry that some people would
> like to conceal any relationship between XML Link and HyTime.  This
> would be problematic for several reasons, among them the fact that some
> potential users will be worried if HyTime is *not* invoked, and (in some
> ways more important) it seems more honest to acknowledge our
> intellectual debts where we can.

There is no worry of that.
 
> I believe there are certainly potential users for whom the mention of
> HyTime will cause fear, trembling, and a mad rush for the exit -- rightly
> or wrongly, HyTime has a fierce reputation as being very hard to
> understand and as making simple things so infernally complicated that
> it could not possibly be worth the trouble to understand it.  This is
> a hard reputation to fight against (as I know to my sorrow, the TEI
> having a similar reputation in some circles).  So it wouldn't surprise
> me if some of us did entertain the thought, from time to time, of
> completing an XML Link spec that never even mentioned HyTime.

Fear is still fear.  It is a bad way to reason.  If some are caught 
in that fear, it is their own problem to be considered.

> It won't happen, though.  If Len is not stark raving mad (I try to keep
> an open mind), then noting the relation of XML Link to HyTime will help
> us with some potential adopters more than it will hurt us with others.

Go ahead and close it.  I am not stark.

However, the normative reference is more than an acknowledgement 
of intellectual parentage.  It is the authoritative reference 
for the boundaries of the development of the subset being 
adopted by XML.  If it is not, and 8879 and 10744 are 
not boundaries, then XML is not the basis for SGML Lite and 
a competitor to XML will be developed.  This isn't a situation 
we should enable by our fears or our tastes... or our ambitions.
 
> A document that makes *normative* references to other
> documents cannot be understood without understanding those documents.

Nor is it bounded.  But it can be understood.
 
> In drafting the original XML language spec, we worked very hard to
> ensure that no *normative* reference to 8879 was necessary. 

That is a mistake.  Conformance to SGML is one of the most 
important features of XML.  If that is not understood by now,
then the ERB should resign en masse and let WG8 do this.

> I claim that there *is* no normative reference to 8879
> in the XML spec.  The conformance of XML documents to 8879 follows as
> a logical consequence of the constraints given in the spec; it does not
> rely on a rule formulated as "You have to do whatever 8879 says you do."

They don't.  We do.  Conformance with SGML, that is, that XML is a 
wholly comforming subset of SGML is the primary constraint.  That 
is why a TC has been offered by WG8's chair.  That is not a light 
matter.  If such conformance is abandoned, the chair of WG8 should 
reconsider that offer, and WG8 should continue with a separate 
and competing version.  It will be ISO, authoritative, and something 
which those whose contracting agreements span nations and considerable 
investment will be made aware of.  It will be XML that dies; not SGML.
 
> I believe David and some others are mostly arguing that we need to
> take the same approach with XML Link.  It will *not* be a good idea
> to say something like
> 
>   "XML Link uses HyTime-style architectural forms as defined in
>   the Extended Facilities Annex.  See that document for notation
>   and meaning of architectural forms."

If they wish to understand the full and authoritative definition of 
AFs, that is precisely what it should say.

 > There are two reasons this would be a bad idea.  (1) We want people
to
> be able to understand XML Link by reading just the XML Link spec;
> any requirements, notation, and semantics we take over from HyTime
> should be documented fully in the XML Link doc.

You gave up your credibility there, Michael.  You nor your group has 
the authority to take over anything.  That is exactly the problem 
with this work.  As for having to read ISO 10744 or ISO 8879, they only 
have to do that if the XML subset is incomplete with respect to 
a developer's requirements.  OTW, why would they read that?

>  (2) HyTime AFs
> have a lot of machinery XML Link will probably not use.  There is no
> need to refer your visitors to a map of the U.S. when all they want to
> know is where the guest bedroom is.

If my visitor wishes to leave a guest bedroom and go to another 
state, that map is of use.  If all they wish to do is sleep in 
the bedroom, why would one offer them that?  It is a facile 
comparison and misses the point:  ISO is authoritative.  XML 
is a set of recommendations from a consortium working group.
That is it's EXACT authoritative status.  Don't confuse these issues.
 
> We know from experience that if you define a simple subset of a
> complex standard by saying "Well, use this standard, but turn off the
> following features," the simple subset might as well not exist.
> For example:  minimal SGML and basic SGML.  No one can understand
> either one without understanding pretty much all of 8879.

That is not the case.  Whatever experience you have, you have 
not learned the lessons it provides.  If you work in the 
industrial side of the SGML community, you know that the 
authoritative references are the ones that can be quoted
in contracts.  That is one reason why ISO HTML is greeted 
with relief.
 
> It is considerations like these, I think, that David has in mind when
> he wants to avoid normative references.  I agree:  normative references
> are for cases where you don't want to have to explain everything the
> reader needs to know.  That should be avoided as far as humanly possible
> in all three of the XML-family specs.

No:  they are the authoritative chain of references which enable 
contractual obligations of all parties.  If you and your committee 
members cannot live with that, resign now.  Otherwise, be aware 
of your obligations to your community.

len bullard
Received on Friday, 21 February 1997 18:28:22 EST

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