W3C home > Mailing lists > Public > w3c-sgml-wg@w3.org > October 1996

Re: A28: syntax of markup declarations?

From: Tim Bray <tbray@textuality.com>
Date: Tue, 08 Oct 1996 09:45:07 -0700
Message-Id: <3.0b33.32.19961008094455.0073e234@pop.intergate.bc.ca>
To: w3c-sgml-wg@w3.org
At 08:41 PM 10/7/96 -0400, Paul Prescod wrote:

>#1. Will an XML document _have_ to have a DTD or DSD to be considered valid?
>And if so, is XML really much of an "easy on-ramp" for authors, or just for
>tool vendors. 

That is an excellent question, which has received relatively little discussion so far.  My personal opinion is that there are actually two levels of validity: an XML document is <term>well-formed</term> if it has correct tag & attribute syntax and all the elements nest properly.  An XML document is <term>valid</term> if parses according to some DTD/DSD.  I think we can all agree that these two levels are easy to understand and are meaningful.  The question of whether the XML spec should discuss both of these in a normative way, and if not, which one, is open and interesting.  Your postings would lead me to suspect you want to discard validation in the SGML sense, and consider a well-formed XML document valid.  Which is a reasonable point of view, but not mine.  At the moment I think that both levels should in fact be defined normatively in the XML spec.

>#2. And if not, how do you feel about the fact that some XML documents will
>not be valid SGML documents (i.e. they will not conform to any DTD).

A display or search application doesn't care all that much.  A professional authoring/publishing tool cares a whole lot.  We should support the needs of both.

Cheers, Tim Bray
tbray@textuality.com http://www.textuality.com/ +1-604-488-1167
Received on Monday, 7 October 1996 21:45:17 UTC

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