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Hi Evan Ideally an Xml processor should not throw away any namespace declarations reduntant or not since sometimes people hack things into serializations depending on a yet unused namespace declaration. The apache serializer - now deprecated had a restriction where there could only be one prefix declared for a given namespace url, so it dropped redundant declarations that someone was depending on for some downstream processing. I realize you can argue the downstream processing should not rely on the upstream declaration - but hacks often make things work. Jim -----Original Message----- From: Evan Lenz [mailto:evan@e...] Sent: Wednesday, July 22, 2009 2:15 PM To: Chuck Bearden Cc: xml-dev@l... Subject: Re: XML processor behavior with unused NS declarations Hi Chuck, Sorry to be late to this thread. It sounds like you've gotten your answer already: don't throw the namespace declaration away. If you're interested in reading some more discussion/background on the reasons why, check out the "QNames in Content" section of a paper/chapter I wrote called "Understanding XML Namespaces".[1] Of course, it's always safe to throw away *redundant* namespace declarations when serializing XML, provided you're not just serializing a fragment (in which case it wouldn't be redundant anymore). For example, if the <h2> element in your example merely repeated the xmlns:dc declaration verbatim, it would be safe to leave that out of your serialized result. (And Canonical XML *requires* such superfluous namespace declarations to be removed.) You just can't make any removals that would make a difference to the XPath data model's abstraction of your document. Evan Lenz Lenz Consulting Group [1] http://lenzconsulting.com/namespaces/#qnames_in_content [2] http://www.w3.org/TR/xml-c14n#SuperfluousNSDecl Chuck Bearden wrote: > Is a namespace-aware XML processor permitted to drop a namespace > declaration when no elements or attributes in that namespace are used > within the scope of the declaration? Say, given this example from the > RDRa Primer: > > <div xmlns:dc="http://purl.org/dc/elements/1.1/"> > <h2 property="dc:title">The trouble with Bob</h2> > <h3 property="dc:creator">Alice</h3> > ... > </div> > > there's no danger of the processor dropping the 'xmlns:dc' > declaration, correct? > > I looked at the Namespaces in XML recommendation, and it doesn't > mention omitting them. A namespace-unaware processor would treat NS > declarations like attributes and hence not drop them, so I reckon that > a NS-aware processor should match that behavior as well, but > confirmation from the cognoscenti is welcome! > > Thanks > Chuck _______________________________________________________________________ XML-DEV is a publicly archived, unmoderated list hosted by OASIS to support XML implementation and development. To minimize spam in the archives, you must subscribe before posting. [Un]Subscribe/change address: http://www.oasis-open.org/mlmanage/ Or unsubscribe: xml-dev-unsubscribe@l... subscribe: xml-dev-subscribe@l... List archive: http://lists.xml.org/archives/xml-dev/ List Guidelines: http://www.oasis-open.org/maillists/guidelines.php
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