>
> I am curious to know to what uses have people put XML processing
> instructions.
W3C doesn't encourage their use for standards, and SOAP processors will
strip them out, so their use is pretty much restricted to publishing
systems.
One PI with wide support is OASIS XML Catalog PIs
http://mail.gnome.org/archives/xml/2002-September/msg00002.html
Most professional XML editors use PIs to place configuration information.
E.g. Topologi Markup Editor has an <?XAR ?> PI which identifies
schema/stylesheet configurations. (IIRC ArborText's editors, Adobe Frame,
Oxygen, all use or can be configured to use PIs.)
There has been some discussion between editor vendors abuot adopting a
common PI for locating DSDL schemas: RELAX NG/Schematron/external DTDs and
so on.
PIs allow the clean separation of processing from structure without
requiring that this involves using separate files (the former does not
need to imply the latter!) Since processing is pretty much application
specific,
it would be surprising to see many standard PIs defined.
Cheers
Rick Jelliffe
