What is W3C's official position on use of PI?

Paul Prescod paul at prescod.net
Thu May 13 03:37:15 BST 1999


Don Park wrote:
> 
> Thanks for clearing that up.  Do you what the folks who "regard PIs as
> problematic second-class syntax" recommend for first-class out-of-band
> signaling mechanism?  I wouldn't mind giving up PI if there was an
> alternative.

Well, Liam Quin has been a constant critic of processing instructions.

http://www.mulberrytech.com/xsl/xsl-list/archive/msg03388.html
http://www.lists.ic.ac.uk/hypermail/xml-dev/9811/0203.html

My response:

http://www.mulberrytech.com/xsl/xsl-list/archive/msg03396.html

As I said in that message, the important thing about processing
instructions is that they are invisible to content models. If XML Schemas
invented a way to make elements invisible to content models (like SGML's
inclusion exceptions, but maybe only allowed at the top level) and a way
to add these inclusions to existing schemas easily then processing
instructions could be replaced by these "floating", element types. That
would be neat.

But if there are no floating element types then we still need processing
instructions.

-- 
 Paul Prescod  - ISOGEN Consulting Engineer speaking for only himself
 http://itrc.uwaterloo.ca/~papresco

Diplomatic term: "Regret"
Translation: To care, but not enough to condemn. ("We regret the loss of
             life in Sierra Leone. We have no intention to do anything 
             to stop it, mind you, but we regret that it happened.")
(Brill's Content, Apr. 1999)

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