XML Standards News;
XPointer Becomes a Candidate Recommendation

XML Pointer Language (XPointer) Version 1.0 became a candidate recommendation on June. In the W3C Standards process, a technical report begins as a Working Draft. A Working Draft is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to use W3C working drafts as reference material or to cite them as other than "work in progress". After refinement at the working draft stage, the technical report becomes a Candidate Recommendation. A Candidate Recommendation is work that has received significant review from its immediate technical community. It is an explicit call to those outside of the related Working Groups or the W3C itself for implementation and technical feedback. This specification is considered stable and is made available for public review and comment. At this stage, the specification may still change and the working group warns implementers that early implementation to constrain its ability to make changes to this specification prior to final release. The XPointer Candidate Recommendation comment period closes on September 7, 2000.

XPointer is the language to be used as the basis for a fragment identifier for any URI reference that locates a resource of Internet media type "text/xml" or "application/xml." XPointer is based on the XML Path Language (XPath) It supports addressing into the internal structures of XML documents. It allows us to examine a hierarchical document structure and and point to any of its internal parts based on various properties, such as element types, attribute values, character content, and relative position.

Some special terms have been defined as part of the XPointer Language. Technical terms you should know in order to understand XPointer include:

sub-resource	The portion of an XML resource that is identified by an XPointer. For example, the whole resource being referred to is an XML document, but a sub-resource might be a particular element inside the document.
location-set	An ordered list of document nodes, points, and/or ranges, such as produced by an XPointer expression. This corresponds to the node-set that is produced by XPath expressions, except for the generalization to include points and ranges.
point	A position in XML information. This notion comes from the DOM Level 2 specification's notion of positions; XPointer refers to DOM positions by the term "point" rather than "position" to avoid confusion with XPath positions.
range	An identification of a contiguous selection of all the XML information between a pair of end points.
singleton	A location that consists of a single, contiguous portion of a document. Some XPointers can locate multiple data portions, such as three contiguous "item" element nodes in a "list" or six noncontiguous occurrences of a string in a document. When an XPointer instead locates only a single contiguous data portion such as a range, string range, or single node, that location is said to be a "singleton."