Minority Opinion on Ranges in XPointer

As stated in the XLink WG charter [1], "XPointer is intended to 
specify the fragment identifier syntax when pointing into resources
with XML media types (text/xml, application/xml)."  XPointer will
be required to be implemented by all tools/applications that expect
to be able to resolve a URI reference to an XML resource. 

Some W3C members--including a minority within the XLink WG--hold the 
position that the "range" capability should not be added to XPointer.  
(See [2] for the WG vote in which Arbortext and Oracle dissented with
the majority opinion.) 

There were various use case scenarios used to support the need for
range, and much time was spent discussing them.  While being able
to address ranges (especially in the context of representing a
user selection) is no doubt useful, some of us feel that the costs 
of adding ranges to XPointer exceed the benefits.  (Note that we do
not object to range handling in general but feel that the ability 
to handle ranges belongs at the XLink layer or the application layer
rather than in the fragment syntax layer.)

A range is not one of the "native" structures in an XML parse tree.  
In fact, as defined by the current XPointer draft, range is the one 
construct that allows XPointer to address an ill-balanced chunk of 
XML.  It is the exception to the rule that what XPointer addresses 
is a "well-balanced fragment" (see [3] for the precise definition 
of that term) of the original document tree.  As such, it potentially 
adds a level of complexity not otherwise designed into XPointer that
should not be included in the fragment identifier syntax for all XML
resources.

See also:
[4] for Arbortext's Last Call comments.
[5] for Oracle's Last Call comments.

For additional comments related to XPointer ranges see [6], [7], and [8].

Paul Grosso

(References 1, 2, and 6 are to member-only pages; the rest are public.)

[1] http://www.w3.org/XML/Group/1998/09/linking-charter.html
[2] http://lists.w3.org/Archives/Member/w3c-xml-linking-wg/2000Feb/0025
[3] http://www.w3.org/TR/WD-xml-fragment
[4]
http://lists.w3.org/Archives/Public/www-xml-linking-comments/1999OctDec/0010
[5]
http://lists.w3.org/Archives/Public/www-xml-linking-comments/1999OctDec/0044
[6] http://lists.w3.org/Archives/Member/w3c-xml-linking-wg/1999Dec/0074
[7]
http://lists.w3.org/Archives/Public/www-xml-linking-comments/1999OctDec/0046
[8]
http://lists.w3.org/Archives/Public/www-xml-linking-comments/1999OctDec/0041

Received on Thursday, 10 February 2000 14:46:13 UTC