XPointer allows you to walk the tree of nodes that an XML document is comprised of to address a specific node or nodes. XPointer expands the syntax set forth by XPath to provide a means of creating fragment identifiers, which are used to specify parts of documents. XPointer provides considerably more control over the referencing of XML document data than the hyperlink approach employed by HTML. For example, XPointer allows you to do things such as address an element with a given value within a list of elements of a given type. You use XPointer
At the time of this writing (June 2005), the standard Windows Forms .NET TreeView control doesn't support the concept of databinding like the ASP.NET TreeView control does. So, we are left writing our own solutions. Recently, I was assigned a UI project exploration task regarding the use of databinding with the Windows Forms .NET TreeView control. This functionality would enable us to quickly develop user-friendly ways to create complex data analysis models for a new application we're designing. By the time I was done, I had written a custom class
XML Linking, formerly known as XLink and as XLL (the eXtensible Linking Language), is a work in progress of the Web Consortium. It is closely related to the XML Recommendation, but adds functionality for high-function hypertext and hypermedia. It is now an independent Working Group, but its projects were started under the main XML Working Group, and progressed to solid Working Drafts there before being handed off to the new XML Linking Working Group.
The work of this WG has two parts: XLink proper provide advanced linking capabilities such as
Description:If you've been paying attention to this column over the past few weeks, you'll already be familiar with XPath and XLink, two important pieces of the XML jigsaw. XPath provides a standard way to access specific nodes (or sets of nodes) within an XML document, while XLink offers XML document authors the ability to link XML data together in a myriad of different ways.
XPointer is a language for locating data within an Extensible Markup Language (XML) document based on properties such as location within the document, character content, and
XPointer provides a more fine-grained addressing than XPath.
* Instead of just nodes, XPointers address locations, which can be nodes, points, or ranges.
* A point can represent the location preceding or following any individual character in e.g. chardata nodes.
The special node test
point()
selects the set of points of a node.
* A range consists of two points in the same document, and is specified using a special range-to location step construct.
* XPointer provides some extra functions:
here() get location of element
XPointer is based largely upon a widely-used technology, the Text Encoding Initiative "extended pointer" [Sperberg-McQueen 1994], [Ide 1995]. Extended pointers provide axes for navigating within trees and a rudimentary predicate language for selecting nodes along axes, and have been implemented in several SGML-based browsing systems.
TEI extended pointers introduced "location terms" including root, here, id, child, descendant, ancestor, previous (sibling), next (sibling), preceding, following, and pattern (content matching by regular expressions) --