XML in a Nutshell, 3rd Edition

Templates and Template Rules

To control what output is created from what input, you add template rules to the XSLT stylesheet. Each template rule is represented by an xsl:template element. This element has a match attribute that contains a pattern identifying the input it matches; it also contains a template that is instantiated and output when the pattern is matched. The terminology is a little tricky here: the xsl:template element is a template rule that contains a template. An xsl:template element is not itself the template.

The simplest match pattern is an element name. Thus, this template rule says that every time a person element is seen, the stylesheet processor should emit the text “A Person”:

<xsl:template match="person">A Person</xsl:template>

Example 8-4 is a complete stylesheet that uses this template rule.

Example 8-4. An XSLT stylesheet with a match pattern

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
     
  <xsl:template match="person">A Person</xsl:template>
     
</xsl:stylesheet>

Applying this stylesheet to the document in Example 8-1 produces this output:

<?xml version="1.0" encoding="utf-8"?>
     
 A Person
     
 A Person

There were two person elements in the input document. Each time the processor saw one, it emitted the text “A Person”. The whitespace outside the person elements was preserved, but everything inside the person elements was replaced by the contents of the template rule, which is called the template.

The text “A Person” ...