The xsl:apply-templates element causes navigation from the current element, usually
but not necessarily to process its children. Each selected node is processed using
the best-match xsl:template defined for that node.
The xsl:apply-templates element takes an optional attribute, mode, which identifies the
processing mode. If this attribute is present, only templates with a matching mode parameter will
be considered when searching for the rule to apply to the selected elements.
It also takes an optional attribute, select.
If the select attribute is omitted, apply-templates causes all the immediate
children of the current node to be processed: that is, child elements and
character content, in the order in which it appears. Character content must be processed by
a template whose match pattern will be something like */text(). Child elements similarly
are processed using the appropriate template,
selected according to the rules given below under xsl:template.
If the select attribute is included, the result must be a sequence of nodes.
All nodes selected by the expression are processed.
The xsl:apply-templates element is usually empty, in which case the selected nodes are
processed in the order they are selected (this will usually be document order, but this depends on the
select expression that is used). However the element may include xsl:sort and/or
xsl:param elements:
For sorted processing, one or more child xsl:sort elements may be included. These define the sort order to be applied to the selection. The sort keys are listed in major-to-minor order.
To supply parameters to the called template, one or more xsl:with-param elements
may be included. The values of these parameters are available to the called template. If the
xsl:with-param element specifies tunnel="yes", then the parameter is passed
transparently through to templates called at any depth, but it can only be referenced by an
xsl:param element that also specifies tunnel="yes". If the default value,
tunnel="no" is used, then the parameter value is available only in the immediately
called template, and only if the xsl:param element specifies tunnel="no"
(explicitly or by defaulting the attribute).
The selected nodes are processed in a particular context. This context includes:
A current node: the node being processed
A current node list: the list of nodes being processed, in the order they are processed (this affects the value of the position() and last() functions)
A set of variables, which initially is those variable defined as parameters
Some examples of the most useful forms of select expression are listed below:
|
Expression |
Meaning |
|
XXX |
Process all immediate child elements with tag XXX |
|
* |
Process all immediate child elements (but not character data within the element) |
|
../TITLE |
Process the TITLE children of the parent element |
|
XXX[@AAA] |
Process all XXX child elements having an attribute named AAA |
|
@* |
Process all attributes of the current element |
|
*/ZZZ |
Process all grandchild ZZZ elements |
|
XXX[ZZZ] |
Process all child XXX elements that have a child ZZZ |
|
XXX[@WIDTH and not(@width="20")] |
Process all child XXX elements that have a WIDTH attribute whose value is not "20" |
|
AUTHOR[1] |
Process the first child AUTHOR element |
|
APPENDIX[@NUMBER][last()] |
Process the last child APPENDIX element having a NUMBER attribute |
|
APPENDIX[last()][@NUMBER] |
Process the last child APPENDIX element provided it has a NUMBER attribute |
The full syntax of select expressions is outlined in XPath Expression Syntax.
