WebReference.com - Excerpt from Inside XSLT, Chapter 2, Part 3 (1/5)

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Inside XSLT

The <xsl:template> Element

XSL templates enable you to specify how you want your transformation to work. Each <sxl:template> element is set up to match one node (which may contain other nodes) or a number of nodes in the source document, and to specify exactly how that node should be transformed.

The following list describes the attributes of <xsl:template>:

• match (optional). Specifies a pattern that matches nodes to be processed. Set to a valid pattern.
• name (optional). Holds the name of the template, which enables it to be called. If you do not use this attribute, you must use the match attribute. Set to a QName.
• priority (optional). A positive or negative integer or real number that sets the priority of this template. Used when more than one template matches the same node. Set to a number.
• mode (optional). If you use <xsl:apply-templates> on a set of nodes, the only templates used have a matching mode. Set to a QName.

Each such <xsl:template> element is called a rule. In general, the <xsl:template> element can contain zero or more <xsl:param> elements (which you'll see in Chapter 9), followed by the template body, which specifies how you want the transformation to take place.

Template Bodies

Templates have very specific rules. They can contain <xsl:param> elements, followed by a template body, which can contain PCDATA, XSLT instructions, extension elements, and literal result elements.

XSLT Instructions

A number of XSLT elements, called instructions, may appear in a template body:

• <xsl:apply-imports>
• <xsl:apply-templates>
• <xsl:attribute>
• <xsl:call-template>
• <xsl:choose>
• <xsl:comment>
• <xsl:copy>
• <xsl:copy-of>
• <xsl:element>
• <xsl:fallback>
• <xsl:for-each>
• <xsl:if>
• <xsl:message>
• <xsl:number>
• <xsl:processing-instruction>
• <xsl:text>
• <xsl:value-of>
• <xsl:variable>

No other XSLT element may appear directly in a template body. As you'll see in Chapter 9, the <xsl:param> element may appear in a template before the template body, but it is not called an XSLT instruction. In addition, other XSLT elements, such as <xsl:sort>, <xsl:otherwise>, <xsl:with-param>, can appear in templates, but only at specific locations, so W3C doesn't call them instructions. You'll see how to use each of these instructions throughout this book.

Extension Elements

Extension elements are covered in Chapter 5; these elements are defined by the user or the XSLT processor, and extend XSLT. Many XSLT processors have defined their own extensions, and that's one of the reasons W3C has introduced the XSLT 1.1 working draft, where the extension mechanism is more regulated. Presumably, this functionality will be incorporated into XSLT 2.0.

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Created: September 26, 2001
Revised: September 26, 2001

URL: https://webreference.com/authoring/languages/xml/insidexslt/chap2/3/