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RE: The purpose of a namespace URI is ...

• From: "Costello, Roger L." <costello@mitre.org>
• To: "xml-dev@lists.xml.org" <xml-dev@lists.xml.org>
• Date: Fri, 30 Nov 2012 15:06:57 +0000

Hello Ken,

At 2012-11-30 12:35 +0000, Costello, Roger L. wrote:
>>     A namespace URI conventionally identifies
>>     the component, subsystem, or authority
>>     responsible for defining the meaning of
>>     an XML vocabulary.
>>
>>Do you agree?

Ken responded:
>A namespace URI only distinguishes one XML vocabulary 
> from another in  a single XML document.
> ... snip ...

 In the XPath and XQuery Functions and Operators document [1] it defines the error() function: the first argument is "code" which is an xs:QName value. An xs:QName, of course has two parts: a namespace part and a local part. The document says that the purpose of the namespace part is to indicate who -- a component, a subsystem, or an authority -- is responsible for the meaning of the local part (the "local part" is, of course, the markup -- the XML vocabulary):

    The $code is an error code that distinguishes this 
    error from others. It is an xs:QName; the namespace 
    URI conventionally identifies the component, subsystem, 
    or authority responsible for defining the meaning of the 
    error code, while the local part identifies the specific 
    error condition. 

This suggests to me that the W3C (or at least the XPath and XQuery portion of the W3C) does not see namespaces as "only distinguishes one XML vocabulary from another." Indeed not. It suggests to me that they regard a namespace as identifying an entity that is responsible for providing the meaning of the XML vocabulary.

Has the XPath and XQuery working group assigned to "namespaces" a radical and incorrect purpose?

/Roger

[1] http://www.w3.org/TR/xpath-functions-30/#func-error

• Follow-Ups:
  • RE: The purpose of a namespace URI is ...
    • From: "G. Ken Holman" <gkholman@CraneSoftwrights.com>
  • Re: The purpose of a namespace URI is ...
    • From: David Carlisle <davidc@nag.co.uk>

• References:
  • The purpose of a namespace URI is ...
    • From: "Costello, Roger L." <costello@mitre.org>
  • Re: The purpose of a namespace URI is ...
    • From: "G. Ken Holman" <gkholman@CraneSoftwrights.com>