XML in a Nutshell, 3rd Edition

Child Element Location Steps

The second simplest location path is a single element name. This path selects all child elements of the context node with the specified name. For example, the XPath profession refers to all profession child elements of the context node. Exactly which elements these are depends on what the context node is, so this is a relative XPath. For example, if the context node is the Alan Turing person element in Example 9-1, then the location path profession refers to these three profession child elements of that element:

<profession>computer scientist</profession>
<profession>mathematician</profession>
<profession>cryptographer</profession>

However, if the context node is the Richard Feynman person element in Example 9-1, then the XPath profession refers to its single profession child element:

<profession>physicist</profession>

If the context node is the name child element of Richard Feynman or Alan Turing’s person element, then this XPath doesn’t refer to anything at all because neither of those has any profession child elements.

In XSLT, the context node for an XPath expression used in the select attribute of xsl:apply-templates and similar elements is the node that is currently matched. For example, consider the simple stylesheet in Example 9-2. In particular, look at the template rule for the person element. The XSLT processor will activate this rule twice, once for each person node in the document. The first time the context node is set to Alan Turing’s ...