½u¤W½u¤U¡§·m¡¨¦~³f¡A¨B¨B°ª¸Õ¤ô¡§¤¬Ápºô+¦~©]¶º¡¨

The XPointer specification entered CR status 2025-08-08, then had a second CR 2025-08-08. During the second CR phase, several implementations were identified. Few, however, implemented the whole XPointer specification. Points and Ranges, the principal extensions beyond XPath, were rarely implemented. In early January of 2002, when it became clear that the XPointer specification would not move to PR, the XML Linking Working Group revisted the specification and began to factor it into separate documents:

1. XPointer Framework, which provides for barenames (now known as 'shorthand pointers') and establishes the schemes framework for extensibility.
2. XPointer element() Scheme, which provides a combination of bare name and child sequence addressing in order to locate elements in XML documents (but not any other structure such as attributes, points, or ranges).
3. XPointer xmlns() Scheme, which provides a means for binding namespace prefixes used in XPointers to namespace names, even if the XPointer itself is not carried in an XML document.
4. XPointer xpointer() Scheme, which provided the more advanced, and rarely implemented, capabilities for identifying ranges, points, attributes, etc.

This document discusses the implementation status of the first three specifications, which were issued as Last Call Working Drafts on July 10, 2002.

Citations of XPointer

Synchronized Multimedia Integration Language (SMIL 2.0) W3C Recommendation 07 August 2001

SMIL 2.0 allows, but does not require, general XPointers. However, it does use barename identifiers in the same manner as the XPointer Framework.

Scalable Vector Graphics (SVG) 1.0 SpecificationW3C Recommendation 04 September 2001

SVG uses barename identifiers. It also defines its own scheme, svgView().

XML-Signature Syntax and Processing W3C Recommendation 12 February 2002

XML Signatures makes use of barename addressing, and recommends that applications support predefined fragments in the xpointer() scheme.

XML Inclusions (XInclude) Version 1.0 W3C Candidate Recommendation 17 September 2002

Requires support for the framework and element() scheme, and allows support for additional schemes.

The XPointer xpath1() SchemeIETF Internet Draft draft-stlaurent-xpath-frag-00.txt

This Internet Draft proposes a new XPointer scheme, xpath1(). This shows the schemes portion of the framework being picked up and used by people in the XML community who are not part of the Linking WG.

XPointer Software

The table below lists the implementaion reports gathered during the CR period. The implementations in that table are for the more complex CR specification. The columns in the table list particular features of the specification, in order to determin how complete the implementations were.

For the three Last-Call drafts, three columns are of particular interest. The "Bare names" column indicates if the implementation will likely support the Framework spec. The "Child sequences" column indicates if the implementation will support the elements() scheme. (Note, however, that the implementations would have to be modified slightly to detect the occurance of the 'element' scheme name, which was not used in the CR draft.) The third column of particular interest is 'Namespace support', which is relevant to the xmlns() scheme.

Implementation Plans

Vendors in the XML Linking Working Group were polled during a recent teleconference (Member-only link) about their current and planned support for the three specifications. Their statements were:

Microsoft

Plans to build XInclude processor including framework and element() scheme support.

Oracle

Currently implementing all three specifications for product. Beta release scheduled for January 2003.

AOL/Netscape

Netscape has already implemented the FIXPTR proposal, but needs to update it to support the new syntax for the element() scheme name.

Fujitsu

Currently supports all features from last CR. Only element() syntax of child sequences not currently supported. Currently working to support all features.

Others

The implementation from Univ. Bologna will also need similar modifications.

Ron Daniel Jr., 2025-08-08