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Working with XSLT Instructions in XSLT Mapper

As described in Graphical Support for Common XSLT Instructions and Expressions, you can create and work with XSLT instructions in the XSLT mapper using symbols called blocks. Each supported instruction is represented by a different block (symbols distinguish one block from another), and you complete the instruction's definition graphically, using drag and drop.

This section identifies the XSLT instructions supported by the mapper, their features, and how to use them. It covers the following topics:

What XSLT Instructions Are Represented Graphically

The XSLT mapper represents the following XSLT instructions:

Table 34. XSLT Instruction Blocks in XSLT Mapper

XSLT Instruction	Representation in the XSLT Mapper
xsl:value-of
xsl:for-each
xsl:if
xsl:choose
xsl:apply-templates
xsl:call-template

Instruction Block Ports

All XSLT instruction blocks have at least three connectors, called ports. Look at the xsl:value-of instruction block shown in Figure 222.

Figure 222. Example of an XSLT xsl:value-of Instruction Block

You use these ports to link source and target nodes, to perform processing on source document nodes, and to provide flow control as the result of a xsl:choose or xsl:if.

Ports are also part of XPath and Java function blocks, logical operator blocks, and text blocks. (See Processing Source Nodes for information on working with these types of blocks.)

Specifying Values for Ports

After you have added an instruction block to the XSLT mapper, you need to complete its definition. You do this by linking the instruction block's input, output, and, optionally, flow ports to nodes and other blocks in the mapper.

The way you specify values for ports varies slightly between input ports and flow and output ports, but, generally speaking, you can either

Understanding Input Ports

Stylus Studio interprets input ports differently for different XSLT instructions, as shown in Table 35:

Specifying Values for Input Ports

You can specify values for input ports by:

Red Input Ports

If an xsl: instruction's attribute takes a literal or string value (such as xsl:value-of select="'Recommended'"/, for example) and a value has been provided for the attribute, Stylus Studio fills the input port associated with that attribute with a deep red to indicate that a value has been specified.

The Flow Port

Output ports for any of the following xsl: instructions can be linked to the flow port of an instruction block:

You might decide you want a particular xsl:for-each instruction executed only after performing a certain function, for example.

Adding an Instruction Block to the XSLT Mapper

To add an instruction block to the XSLT mapper

The shortcut menu appears.

The XSLT Instructions submenu appears.

The block for the instruction you selected appears in the mapper canvas.

Notes About Creating Instruction Blocks

Be aware of the following when working with XSLT instruction blocks in the XSLT mapper:

Editing xsl: Instruction Properties

You can change or specify the properties associated with an xsl: instruction by editing the instructions properties. Each xsl: instruction block (and blocks for XPath functions) is associated with a dialog box that allows you to edit its basic properties, like this Function Property dialog box for the contains function.

Figure 224. Properties Dialog Box for an XPath Function

To edit xsl: instruction properties:

Stylus Studio displays the properties dialog box for the XSLT instruction or XPath function you selected from the mapper.

xsl:if and xsl:choose

The xsl:if instruction cannot express an else condition. It has a single input port, and a single output port, as shown in Figure 225.

Figure 225. xsl:if Instruction Block

Once fully defined, the xsl:if block generates code like the following:

<Review>
               
	<xsl:if test="authors/author= 'Minollo'">
               
		<xsl:value-of select="'Recommended'"/>
               
	</xsl:if>
               
	<xsl:if test="contains(authors/author,'Pedruzzi')">
               
		<xsl:value-of select="'A best buy'"/>
               
	</xsl:if>
               
</Review>
               

            

If you need to express an else condition, use the xsl:choose instruction block. This instruction block has two output ports by default, one for the xsl:when test= attribute, and one for the one xsl:otherwise element.

Figure 226. xsl:choose Instruction Block

The xsl:choose instruction block generates code like the following:

<Review>
               
	<xsl:choose>
               
		<xsl:when test="authors/author= 'Minollo'">
               
			<xsl:value-of select="'Recommended'"/>
               
		</xsl:when>
               
		<xsl:when test="contains(authors/author,'Pedruzzi')">
               
			<xsl:value-of select="'authors best buy'"/>
               
		</xsl:when>
               
		<xsl:otherwise>
               
			<xsl:value-of select="'bah...'"/>
               
		</xsl:otherwise>
               
	</xsl:choose>
               
</Review>
               

            

If you need to define more than one xsl:when test= attribute, use the xsl:choose properties dialog box for the xsl:choose instruction block.

Editing xsl:choose Instruction Properties

Use this procedure to

To edit xsl:choose properties:

The xsl:choose properties dialog box appears. Any attributes already defined for the xsl:choose instruction you are editing are displayed in the xsl:test conditions list box

Figure 227. Properties Dialog Box for xsl:choose

A new entry field appears.