XPointer
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.[1] [2]
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.
XPointer is covered by a royalty-free technology patent held by Sun Microsystems (expired 2016-02-01).[3]
Positional Element Addressing
The element()
scheme 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))
References
- "XPointer Framework". Retrieved April 13, 2009.
- "XML and Semantic Web W3C Standards Timeline" (PDF).
- "XPointer Patent Statements". www.w3.org.
See also
- URI fragment
- HTML
- HyTime
- Text Encoding Initiative Guidelines
- XML