W3C home > Mailing lists > Public > www-html@w3.org > January 2000

Re: Why DOCTYPE Declarations for XHTML?

From: Murray Altheim <altheim@eng.sun.com>
Date: Fri, 14 Jan 2000 10:38:46 -0800
Message-ID: <387F6D36.3463E68C@eng.sun.com>
To: Arjun Ray <aray@q2.net>
CC: www-html@w3.org
Arjun Ray wrote:
> On Fri, 14 Jan 2000, Dave Raggett wrote:
> > The doctype is the means to bind the document to a DTD,
> Not really: a DTD is not an independent object that has or needs to be
> bound.  The relevant declarations are syntactically an integral part of
> the document, and one of the purposes of the doctype declaration is to
> incorporate - not refer to - any declarations relevant to the instance
> markup.  As the discussion in the SGML Handbook (p 402ff on Clause 11)
> makes quite clear, the external subset per se is superfluous - indeed, Dr.
> Goldfarb once proposed that it should be eliminated in XML! - because

Arjun, stop the pontificating for a minute. What are you realistically
trying to accomplish here? I can't see it past the verbage.

We're trying to create normative specification based on the XML 1.0 
Recommendation. Nothing more, nothing less. We've created a "markup
language" called XHTML that is specified via DTD, and the way in XML 1.0
that you associate a DTD with an instance (in whatever direction makes
better sense to you) is using a DOCTYPE declaration. If someone figures
out this can be done with a laser beam and an egg, fine, but in terms of
what we currently have available as a means to normatively perform this
task, there's ONE way to do this.

I don't need a lecture on *what* a DTD is or isn't. 

> Goldfarb once proposed that it should be eliminated in XML! - because
>   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN">
> is just syntactic sugar for
>   <!DOCTYPE html [
>    <!ENTITY % dtd PUBLIC "-//W3C//DTD XHTML 1.1//EN">
>    %dtd; ]>

You can't put a conditional section in an internal subset. Your statement
is untrue in XML 1.0.

> I'm not sure why the essential requirement - validity with
> respect to a *specific* set of declarations - wasn't simply stated in
> general terms (as Erik Naggum implies), leaving the determination open to
> alternatives in methods.

If you were to read the Modularization document, you might note that we 
went to great trouble to define XHTML abstractly so that it would be 
possible to create a conformant XML Schema. 

But for associating DTDs with instances in XML 1.0, there are no normative
'alternatives in methods', and we're trying to guarantee interoperability 
of XHTML documents, not open the world for laser beams and eggs.


Murray Altheim                                   <mailto:altheim@sonic.net>
Member of Technical Staff, Tools Development & Support
Sun Microsystems, Inc. MS MPK17-102
1601 Willow Rd., Menlo Park, California 94025  <mailto:altheim@eng.sun.com>

   the honey bee is sad and cross and wicked as a weasel
   and when she perches on you boss she leaves a little measle -- archy
Received on Friday, 14 January 2000 13:45:15 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 7 January 2015 15:05:52 UTC