XML XPointer Requirements, Version 1.0

For the most part, I have fewer concerns with XPointers than I do with
XLink, but the concerns I do have would probably be addressed by a fairly
drastic step, the use of a 'Level' approach like that used in the CSS and
DOM WGs.

XPointers that refer to well-formed chunks of XML are easy to describe and
easy to implement.  This subset has enormous usage potential outside the
fairly narrow set of tools used to support linking, and development using
XPointer to reference objects generated from XML document processing is
already underway.  This subset is relatively uncontroversial, and would
make a good 'Level 1'.

The other set of XPointers are far more critical for use in text annotation
and complex linking.  As a developer whose hypertext interests derive from
work with historical documents, I definitely want to be able to create
links whose ends aren't well-formed, cross element boundaries at will, or
may appear multiple times in the same document (keywords.)  At the same
time, however, I recognize that implementing XPointers whose targets are
not simple elements is a difficult problem that can interfere with many of
the tasks I described in the previous paragraph.  As a result, I would
suggest that these XPointers be described in a 'Level 2' document, making
them available to developers who need this sophistication but without
imposing on developers who only need 'Level 1.'

While some may point out that partial implementations are something that
happens all the time, 'official' recognition of this fact and the creation
of a vocabulary to describe levels of XPointer implementation seems like a
good way to keep developers happy while allowing users to find and take
advantage of the tools they actually need.

Simon St.Laurent
XML: A Primer
Sharing Bandwidth / Cookies
http://www.simonstl.com

Received on Monday, 22 March 1999 13:15:40 UTC