xslt 1.0 节点集错误，转换无效

Question

I have a problem with xslt in 1.0 version. My node looks like this

...
<Garage>
    <car>
       <color>red</color>
       <color>yellow</color>
       <wheel>left</wheel>
    <car/>
</Garage>
...

Then I save child node into variable

<xsl:variable name="entries">
    <xsl:if test="$element/Garage/car">
        <xsl:value-of select="$element/Garage/car"/>
    </xsl:if>
</xsl:variable>

and when I'am using this variable in template

    <xsl:template name="entriesToString">
        <xsl:param name="table"/>
        <xsl:for-each select="$table/color">
            <xsl:if test="position() = last()">
                <xsl:value-of select="concat(current(),'/')"/>
            </xsl:if>
            <xsl:value-of select="concat(current(),',')"/>
        </xsl:for-each>
    </xsl:template>

I get error like this

ERROR:  'Invalid conversion from 'com.sun.org.apache.xalan.internal.xsltc.dom.SimpleResultTreeImpl' to 'node-set'.'

Is there any problem with node iteration in xslt?

Answer 1

In XSLT 1.0, the xsl:value-of instruction creates a text node whose value is the string-value of the first node in the selected node-set.

In your example, the $entries variable is a result-tree-fragment that contains the text "red yellow left" (with or without some white-space characters). In order to process a result-tree-fragment using the xsl:for-each instruction, you must first convert it to a node-set, using a processor-specific extension function. In any case, it wouldn't do you any good in this case, since - as explained above - it contains a single text node.

Answer 2

It might suffice to use <xsl:variable name="entries" select="$element/Garage/car"/> , that way you have a node-set in XPath/XSLT 1, without the need to use an extension function. The node-set is empty if the path $element/Garage/car doesn't select anything, it contains car element nodes from $element if they exist, ie the path $element/Garage/car selects something.