XML 1.0 and XML 1.1

This is very interesting.
RI

-----Original Message-----
From: chairs-request@w3.org [mailto:chairs-request@w3.org] On Behalf Of
Grosso, Paul
Sent: 29 October 2007 15:20
To: chairs@w3.org
Subject: XML 1.0 and XML 1.1


Chairs,

Please feel free to forward this email to your WGs.  (Public W3C mailing
lists are fine--this is not intended to be member-only.)

paul

------

Since XML 1.1 became a W3C Recommendation in August 2006, there has been a
substantial uptake of it as a peer of XML 1.0 in new and ongoing W3C work.
This is appropriate, as XML 1.1 was explicitly not designed to replace XML
1.0, but to supplement it for the benefit of various groups against which
XML 1.0 had unjustly, but unintentionally, discriminated.

However, there are very few XML 1.1 documents in the wild.  
The XML Core WG believes this to be the result of a vicious cycle, in which
widely distributed XML parsers do not support 1.1 because the parser authors
believe that few document authors will use it.
This becomes a self-fulfilling prophecy, as those who would benefit from XML
1.1 are rightfully concerned that documents written in it will not be widely
acceptable.

After considering various other ideas, the XML Core WG wants to suggest the
possibility of changing XML 1.0 to relax the restrictions on element and
attribute names thereby providing in XML 1.0 the major end user benefit
currently achievable only by using XML 1.1.

To quote the XML 1.1 Recommendation:

 The W3C's XML 1.0 Recommendation was first issued in 1998,  and despite the
issuance of many errata culminating in a  Third Edition of 2004, has
remained (by intention) unchanged  with respect to what is well-formed XML
and what is not.
 This stability has been extremely useful for interoperability.
 However, the Unicode Standard on which XML 1.0 relies for  character
specifications has not remained static, evolving from
 version 2.0 to version 4.0 and beyond.	Characters not present
 in Unicode 2.0 may already be used in XML 1.0 character data.
 However, they are not allowed in XML names such as element type  names,
attribute names, enumerated attribute values, processing  instruction
targets, and so on.  In addition, some characters  that should have been
permitted in XML names were not, due to  oversights and inconsistencies in
Unicode 2.0.

 The overall philosophy of names has changed since XML 1.0.
 Whereas XML 1.0 provided a rigid definition of names, wherein  everything
that was not permitted was forbidden, XML 1.1 names are  designed so that
everything that is not forbidden (for a specific
 reason) is permitted.  Since Unicode will continue to grow past  version
4.0, further changes to XML can be avoided by allowing  almost any
character, including those not yet assigned, in names.

Since then, Unicode has expanded further to reach 5.0, and it is nowhere
near complete with respect to the world's minority languages and writing
systems.  If XML 1.0 relaxed the restrictions on element and attribute
names, those who preferred to retain the Appendix B constraints in their
documents would be free to do so, but those who wish to use element and
attribute names in languages normally written in any of the Ethiopic,
Cherokee, Canadian Syllabics, Khmer, Mongolian, Yi, Philippine, New Tai Lue,
Buginese, Syloti Nagri, N'Ko, and Tifinagh scripts will be able to do so, as
will users of minority languages whose scripts appeared in Unicode 2.0 but
were lacking essential letters for writing those languages.

Of course, older parsers will still reject such documents, but there will be
no need for a strict XML 1.0/1.1 dichotomy.  The XML Core WG has heard
evidence tending to indicate that implementing such a relaxation would be
technically straightforward in essentially all XML parsers:  it is a matter
of replacing a rather large "permitted" table with a much smaller
"forbidden" table.

The XML Core WG assumes that if such an erratum were to be passed into XML
1.0, the XML 1.1 Recommendation would eventually be deprecated by the W3C.

Comments on all aspects of this possibility are earnestly solicited; please
send them to www-xml-blueberry-comments@w3.org (publicly archived).

Paul Grosso
for the XML Core WG

Received on Tuesday, 30 October 2007 12:53:35 UTC