XPointer is a system for addressing components of XML-based Internet media. It is divided among four specifications: a "framework" that forms the basis for identifying XML fragments, a positional element addressing scheme, a scheme for namespaces, and a scheme for XPath-based addressing. XPointer Framework is a W3C recommendation since March 2003.
The XPointer language is designed to address structural aspects of XML, including text content and other information objects created as a result of parsing the document. Thus, it could be used to point to a section of a document highlighted by a user through a mouse drag action.
During development, and until 2016, XPointer was covered by a royalty-free technology patent held by Sun Microsystems.
Positional element addressing
The element() scheme4 introduces positional addressing of child elements. This is similar to a simple XPath address, but subsequent steps can only be numbers representing the position of a descendant relative to its branch on the tree.
For instance, given the following fragment:
<foobar id="foo"> <bar/> <baz> <bom a="1"/> </baz> <bom a="2"/> </foobar>results as the following examples:
xpointer(id("foo")) => foobar xpointer(/foobar/1) => bar xpointer(//bom) => bom (a=1), bom (a=2) element(/1/2/1) => bom (a=1) (/1 descend into first element (foobar), /2 descend into second child element (baz), /1 select first child element (bom))See also
External links
- XPointer Framework
- Namespacing
- Path based addressing
- XPointer patent terms and conditions
- Open source implementation (CognitiveWeb)
- GPL License .NET implementation (XInclude.NET)
- Method and system for implementing hypertext scroll attributes on Google Patents, expired 2016-02-01
References
Grosso, Paul; Maler, Eve; Marsh, Jonathan; Walsh, Norman, eds. (2003-03-25). "XPointer Framework". W3C. W3C. Retrieved 2021-04-08. http://www.w3.org/TR/2003/REC-xptr-framework-20030325/ ↩
Bikakis N.; Tsinaraki C.; Gioldasis N.; Stavrakantonakis I.; Christodoulakis S. "The XML and Semantic Web Worlds: Technologies, Interoperability and Integration. A survey of the State of the Art" (PDF). Archived from the original (PDF) on 2019-10-26. Retrieved 2021-04-08. https://web.archive.org/web/20191026052918/http://www.dblab.ntua.gr/~bikakis/XML%20and%20Semantic%20Web%20W3C%20Standards%20Timeline-History.pdf ↩
Daniel, Ron (2002-06-10). "XPointer Patent Statements". www.w3.org. Retrieved 2021-04-08. http://www.w3.org/2002/06/xptr_IPR_summary.html ↩
Grosso, Paul; Maler, Eve; Marsh, Jonathan; Walsh, Norman, eds. (2003-03-23). "XPointer element() Scheme". W3C. W3C. Retrieved 2021-04-08. https://www.w3.org/TR/xptr-element/ ↩