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XPointer Working Drafts

Date:      Thu, 11 Jul 2002 09:01:46 -0400 (EDT)
From:      John Cowan <>
Subject:   XPointer

The XML Linking WG has just published four XPointer Working Drafts, representing the dissection of XPointer into a general framework and multiple independent schemes: element(), xmlns(), and xpointer().

The framework document deals with bare identifiers (which can be DTD or WXS-based IDs) and with the general syntax of schemes.

The element() scheme allows references into frozen documents that don't have IDs present, using a syntax like "element(/1/2/3)" to mean the 3rd child of the 2nd child of the root element, or "element(foo/4/5)" to mean the 5th child of the 4th child of the element whose ID is "foo".

The xmlns() scheme provides a namespace context for XPath expressions in the xpointer() scheme; XPointers do *not* inherit the namespace context of the document in which they are embedded.

The xpointer() scheme, which is not yet a Last Call draft due to known minor editorial and definitional problems, provides for general reference into documents using XPath, extended by the here() and origin() functions for use with XLink, and the concept of points (similar to DOM Level 2 positions) and ranges (similar to DOM Level 2 ranges) to allow arbitrary transclusions.

The possibility that other schemes will be added remains open.

The purpose of factoring these schemes is to permit other standards to claim conformance to any or all of these documents (although it makes no sense to claim conformance to a scheme without also claiming conformance to the framework.

Because this is primarily a refactoring effort without any new semantics (except WXS-compliant IDs), and only trivial changes to syntax, these documents will probably go straight from Last Call to Proposed Recommendation; the review period is only three weeks. So get your comments in early and often.

	All that is gold does not glitter,
	Not all those who wander are lost;
	The old that is strong does not wither,
	Deep roots are not reached by the frost.

	From the ashes a fire shall awaken,
	A light from the shadows shall spring;
	Renewed shall be blade that was broken,
	The crownless again shall be king.
		--Bilbo Baggins
-- John Cowan                 
At times of peril or dubitation
Perform swift circular ambulation
With loud and high-pitched ululation.

Prepared by Robin Cover for The XML Cover Pages archive. See details in the news item 2002-07-11.

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