SGML: XML Progress [January 1997]
Subject: Re: XML Progress ?
Date: 8 Jan 1997 23:33:23 GMT
From: firstname.lastname@example.org (Jon Bosak)
| Like most people at SGML '97, I was very enthusiastic about the XML
| format. I got a copy of the (DRAFT) spec at the show, but would now
| like to know a few things regarding progress, or lack of progress. I
| guess this posting is aimed at those working on XML.
Let's hit the general sources of information first and then get to the
more detailed questions.
The W3C SGML Activity, which is the effort responsible for XML, is
publicly described by a Web page on the W3C site:
This page changes very slowly, but it does describe the overall
effort, including its specific deliverables. These are being
developed in three phases, currently described as follows:
Phase I: A specification for XML (Extensible Markup Language), a
simplified version of SGML suitable for Internet applications.
Target delivery: draft by the SGML 96 Conference (Boston, November
Phase II: A specification of standard hypertext mechanisms for
Internet SGML applications. Target delivery: draft by the WWW6
Conference (Santa Clara, April 1997).
Phase III: Public text and extensions needed to apply the DSSSL
stylesheet language (ISO/IEC 10179) to Web browsers. Target
delivery: draft by the SGML 97 Conference (Washington, December
We are currently about three weeks into Phase II, which will
eventually produce a separate draft that is being referred to by the
working title "xml-link".
If you are interested in following the discussion, you should be able
to monitor the message archive site for the Working Group at
Unfortunately, this archive appears to have become stuck somewhere
around the middle of September. There's also a thread index of that
That one goes clear up to the middle of October. If you really want
to know what's going on, there is a collection of the mail on the
Working Group list that gets informally updated evey couple of weeks
and put in an anonymous FTP archive at sunsite.unc.edu in the
directory /pub/sun-info/standards/xml/wg. These files can also be
downloaded using HTTP and a Web browser by accessing the following
The volume of mail is staggering, but if you need to know, this is the
place to look. The latest file, 9612b, is devoted in large part to a
dense but illuminating discussion of hypertext linking.
Now for your more detailed questions.
| First, is the Draft 1.0 version likely to become the REAL 1.0 version
| in its current form?
In most essential respects, yes.
| I would like to start working with XML, but I am put off by the
| uncertainty. I assume some changes will occur (I heard about
| re-admitting PUBLIC identifiers, for example), but at least a vague
| indication of the number and nature of such changes would be very
| welcome at this stage.
1. PUBLIC identifiers definitely will be added to the current draft.
The big question is whether the XML specification will say anything
about a resolution mechanism. Work on this has been spun off to an ad
hoc subcommittee that is expected to come back with a set of
recommendations about a month from now.
2. Following one last round of the great RS/RE debate (see archive
file 9612a), the rules for handling whitespace were revised by a
decision of the SGML ERB that was announced by XML draft co-editor Tim
Bray on December 18. You can find this in the archive file 9612b
under the subject line "ERB decisions on RS/RE and whitespace".
3. The design of several features of the November XML draft was forced
by the requirement for compatibility with ISO 8879. Following the
rollout at SGML 96, some members of ISO/IEC JTC1/SC18/WG8 suggested
the possibility that a Technical Corrigendum to 8879 might be approved
to address these areas in advance of the long-planned SGML revision.
We are continuing to explore this possibility. If WG8 approves an XML
TC to 8879, some of the features included for 8879 compatibility will
change. This would include the prohibition of overlapping attribute
values and the prohibition of double hyphens in comments. However,
the prohibition of ambiguous content models would remain.
4. The standard XML comment delimiters are about to change. Comments
will begin with <!--* and end with *-->. A formal resolution to this
effect is expected in about a week.
The editors plan to reorganize some sections of the document to
improve readability, but everything else in the November XML draft
should stay substantively the same through the end of the 1.0
| Second, when will we hear more about the standard style-sheet
| mechanism for XML? Will it be DSSSL Light, or follow the Cascading
| styles sheets currently being implemented in HTML?
Stylesheets belong to Phase III of the effort. As stated on the
Activity page, the plan of record calls for the deployment of DSSSL as
the standard stylesheet language for XML. However, nothing in the XML
specification precludes the association of CSS or other stylesheet
languages with XML documents, and in fact several of us expect that
CSS will frequently be used for this purpose, especially CSS style
attributes embedded in XML start-tags.
| Third, what about standard models for complex structures such as
| tables. What about CALS or HTML tables ? I think a standard model
| could only help promote this standard, and I strongly suggest it be
| one of the above models.
The standardization of features beyond the deliverables listed on the
Activity page is outside the scope of the current effort. DSSSL can
already handle CALS tables and a variety of other table markup
Jon Bosak, Online Information Technology Architect, Sun Microsystems
2550 Garcia Ave., MPK17-101, | Best is he that inuents,
Mountain View, California 94043 | the next he that followes
Davenport Group::SGML Open::ANSI X3V1 | forth and eekes out a good
::ISO/IEC JTC1/SC18/WG8::W3C SGML ERB | inuention.