The location paths of XPath 1.0 are referred to in XPath 2.0 as path expressions. Informally, a path expression is a sequence of steps separated by the "/" operator, for example a/b/c (which is short for child::a/child::b/child::c). More formally, however, "/" is simply a binary operator that applies the expression on its right-hand side to each item in turn selected by the expression on the left hand side. So in this example, the expression a selects all the element children of the context node that are named ; the expression child::b is then applied to each of these nodes, selecting all the children of the elements; and the expression child::c is then applied to each node in this sequence, which selects all the elements.
The "/" operator is generalized in XPath 2.0 to allow any kind of expression to be used as an operand: in XPath 1.0, the right-hand side was always an axis step. For example, a function call can be used on the right-hand side. The typing rules for the operator require that the result of the first operand is a sequence of nodes. The right hand operand can return either nodes or atomic values (but not a mixture). If the result consists of nodes, then duplicates are eliminated and the nodes are returned in document order, an ordering defined in terms of the relative positions of the nodes in the original XML tree.
In many cases the operands of "/" will be axis steps: these are largely unchanged from XPath 1.0, and are described in the article on XPath 1.0.
Read more about this topic: XPath 2.0
Famous quotes containing the words path and/or expressions:
“Every path but your own is the path of fate. Keep on your own track, then.”
—Henry David Thoreau (1817–1862)
“Compare the history of the novel to that of rock ‘n’ roll. Both started out a minority taste, became a mass taste, and then splintered into several subgenres. Both have been the typical cultural expressions of classes and epochs. Both started out aggressively fighting for their share of attention, novels attacking the drama, the tract, and the poem, rock attacking jazz and pop and rolling over classical music.”
—W. T. Lhamon, U.S. educator, critic. “Material Differences,” Deliberate Speed: The Origins of a Cultural Style in the American 1950s, Smithsonian (1990)