[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

RE: SAX2 Namespace Support

  • From: David Megginson <david@m...>
  • To: xml-dev <xml-dev@i...>
  • Date: Thu, 6 Jan 2000 13:56:32 -0500 (EST)

RE: SAX2 Namespace Support
Hunter, David writes:

 > > > The problem though boils down to how often, in reality, XML
 > > > instances will have the same Namespace declared twice, with
 > > > different prefixes.
 > > 
 > > The fact that the bug would be rare makes it worse -- an
 > > application will run perfectly for, say, 18 months, then will
 > > suddenly and inexplicably blow up long after the original
 > > programmers have moved on because one input document happened to
 > > declare the same NS twice and the programmers didn't build in
 > > error recovery for that problem.
 > I don't want to flog any dead horses, so I hope this hasn't been covered
 > already, but is it really an error to have the same namespace declared
 > twice, with different prefixes?  

No, it's not an error at all.  We're concerned about the borderline
case where there are two QName objects

  {"http://www.w3c.org/1999/xhtml", "p", ""}
  {"http://www.w3c.org/1999/xhtml", "p", "html"}

and a program compares them with equals() in Java or == in C++.  Most
people are arguing that the two should be equals()/==, but a few
people have pointed out that that is a nasty trap for any programmer
who is not extremely familiar with the Namespaces spec.

My proposed solution is simply to punt: don't introduce a QName class
in SAX2, and leave such things to higher-level specs, which can
deal with these as they see fit.

All the best,


David Megginson                 david@m...

xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i...
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1
To unsubscribe, mailto:majordomo@i... the following message;
unsubscribe xml-dev
To subscribe to the digests, mailto:majordomo@i... the following message;
subscribe xml-dev-digest
List coordinator, Henry Rzepa (mailto:rzepa@i...)


Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!

Buy Stylus Studio Now

Download The World's Best XML IDE!

Accelerate XML development with our award-winning XML IDE - Download a free trial today!

Don't miss another message! Subscribe to this list today.
First Name
Last Name
Subscribe in XML format
RSS 2.0
Atom 0.3

Stylus Studio has published XML-DEV in RSS and ATOM formats, enabling users to easily subcribe to the list from their preferred news reader application.

Stylus Studio Sponsored Links are added links designed to provide related and additional information to the visitors of this website. they were not included by the author in the initial post. To view the content without the Sponsor Links please click here.

Site Map | Privacy Policy | Terms of Use | Trademarks
Free Stylus Studio XML Training:
W3C Member
Stylus Studio® and DataDirect XQuery ™are products from DataDirect Technologies, is a registered trademark of Progress Software Corporation, in the U.S. and other countries. © 2004-2013 All Rights Reserved.