The XML Information Set specification ('Infoset') has been advanced to the status of W3C Candidate Recommendation, and implementation experience is being sought by the WG members. The specification provides an abstract data set via a set of definitions "for use in other specifications that need to refer to the information in an XML document." The Infoset "does not attempt to be exhaustive: the primary criterion for inclusion of an information item or property has been that of expected usefulness in future specifications. Nor does it constitute a minimum set of information that must be returned by an XML processor... The XML Information Set does not require or favor a specific interface or class of interfaces. The specification presents the information set as a modified tree for the sake of clarity and simplicity, but there is no requirement that the XML Information Set be made available through a tree structure. Other types of interfaces, including (but not limited to) event-based and query-based interfaces are also capable of providing information conforming to the XML Information." The W3C XML Core Working Group invites comments on the Infoset CR through 15-June-2001, at which time it expects to have sufficient evidence of implementation to advance the specification to a Proposed Recommendation.

Bibliographical information: XML Information Set. W3C Candidate Recommendation 14-May-2001. Edited by John Cowan and Richard Tobin. Latest version URL: http://www.w3.org/TR/xml-infoset. Appendices: Appendix A: References; Appendix B: XML 1.0 Reporting Requirements (informative); Appendix C: Example; Appendix D: What is not in the Information Set; Appendix E: RDF Schema (informative).

The eleven information items include: The Document Information Item; Element Information Items; Attribute Information Items; Processing Instruction Information Items; Unexpanded Entity Reference Information Items; Character Information Items; Comment Information Items; The Document Type Declaration Information Item; Unparsed Entity Information Items; Notation Information Items; Namespace Information Items.

Candidate Recommendation Plans and Exit Criteria: "The purpose of this XML Information Set specification is to provide definitions for use in other specifications; definitions of what structure is represented by the syntax of an XML document was not included in the original XML specification, but a number of technologies layered on XML have needed such definitions, and have specified them: (1) The Document Object Model is an API for manipulating the structure represented by an XML document. (2) XPath gives a syntax for selecting parts of the structure represented by an XML document; this syntax is defined in terms of a data model; this XPath data model is used in the XSLT and XPointer specifications. (3) The XML Canonicalization specficiation is also based on the XPath data model. (4) The XML Schema specification is defined in terms of the information represented by an XML document, not in terms of the character-sequence syntax. (5) The XInclude specification is defined as merging document structures. (6) The XML Query algebra is based on a data model for XML." [See the posting from Paul Grosso, Co-chair of the W3C XML Core WG.]