Basic XSLT/XSLTC question

[Justine Hlista]

I'm using xalan-j_2_6_0 and trying to get an example from Michael Kay's book to work:

<xsl:template match="/">
<xsl:variable name="rainbow">
<color>red</color>
<color>blue</color>
<color>green</color>
</xsl:variable>

<xsl:for-each select="$rainbow/color">
<xsl:value-of select="."/>
</xsl:for-each>
</xsl:template>

Both XSLTC and XSLT generate errors when they encounter the XPath expression in the select attribute. I cannot get XSLTC or XSLT to accept any expression that qualifies a variable in a select statement.

Am I trying to do something that is strictly forbidden here? Am I misunderstanding what Michael Kay's example was supposed to do?

Any help is greatly appreciated!!

Justine

 

[Dimitre Novatchev MVP XML]

I guess that you read the second edition of Mike's book, in which he covered XSLT 1.1.

XSLT 1.1 was never developed by the W3C into a final status and is not a standard. The current standard of XSLT 1.0 has the concept of RTF (Result Tree Fragment).

An RTF cannot be treated like a node-set in XPath -- any such attempt results in raising an error -- this is exactly what you described.

In order to process an RTF as a node-set, one must use an implementation-defined extension function with the usual name of node-set, belonging to an implementation-dependent namespace, or use the common:node-set function as defined by EXSLT.

These functions take an RTF and convert it to a regular node-set. Then their result is a regular tree (a node-set having just one root node) and can be navigated using XPath.

Therefore, you also have to use whatever implementation-defined xxx:node-set extension function is available for your XSLT processor.

Cheers,

Dimitre Novatchev [XML MVP],
FXSL developer, XML Insider,

http://fxsl.sourceforge.net/ -- the home of FXSL
Resume: http://fxsl.sf.net/DNovatchev/Resume/Res.html

 

[Philippe Poulard]

Hi,

It is also possible to store "XML constants" inside your stylesheet and refer to them with the document function, that will be adressable with XPath (no extension required) :

<xsl:stylesheet ...
xmlns:xsl="..."
xmlns:data="...">

<data:structures>
<rainbow>
<color>red</color>
<color>blue</color>
<color>green</color>
</rainbow>
</data:structures>

<xsl:template match="/">
<xsl:variable name="rainbow"
select="document('')/*/data:structures/rainbow"/>
<xsl:for-each select="$rainbow/color">
<xsl:value-of select="."/>
</xsl:for-each>
</xsl:template>

</xsl:stylesheet>

I guess that you read the second edition of Mike's book, in which he covered XSLT 1.1.

XSLT 1.1 was never developed by the W3C into a final status and is not a standard. The current standard of XSLT 1.0 has the concept of RTF (Result Tree Fragment).

An RTF cannot be treated like a node-set in XPath -- any such attempt results in raising an error -- this is exactly what you described.

In order to process an RTF as a node-set, one must use an implementation-defined extension function with the usual name of node-set, belonging to an implementation-dependent namespace, or use the common:node-set function as defined by EXSLT.

These functions take an RTF and convert it to a regular node-set. Then their result is a regular tree (a node-set having just one root node) and can be navigated using XPath.

Therefore, you also have to use whatever implementation-defined xxx:node-set extension function is available for your XSLT processor.

Cheers,

Dimitre Novatchev [XML MVP],
FXSL developer, XML Insider,

http://fxsl.sourceforge.net/ -- the home of FXSL
Resume: http://fxsl.sf.net/DNovatchev/Resume/Res.html

I'm using xalan-j_2_6_0 and trying to get an example from Michael Kay's book to work:

<xsl:template match="/">
<xsl:variable name="rainbow">
<color>red</color>
<color>blue</color>
<color>green</color>
</xsl:variable>

<xsl:for-each select="$rainbow/color">
<xsl:value-of select="."/>
</xsl:for-each>
</xsl:template>

Both XSLTC and XSLT generate errors when they encounter the XPath expression in the select attribute. I cannot get XSLTC or XSLT to accept any expression that qualifies a variable in a select statement.

Am I trying to do something that is strictly forbidden here? Am I misunderstanding what Michael Kay's example was supposed to do?

Any help is greatly appreciated!!

Justine

 

[Dimitre Novatchev MVP XML]

Hi,

It is also possible to store "XML constants" inside your stylesheet and refer to them with the document function, that will be adressable with XPath (no extension required) :

Yes, and this is a really valuable technique for creating data structures to be used by the XSLT application.

The example given by the OP can be solved completely that way.

What cannot be done in this way is to access dynamically created nodes.

Cheers,

Dimitre Novatchev [XML MVP],
FXSL developer, XML Insider,

http://fxsl.sourceforge.net/ -- the home of FXSL
Resume: http://fxsl.sf.net/DNovatchev/Resume/Res.html