RE: [xsl] Dynamic Sorting - Using a variable to determine the sort select e xpression

["Diamond, Jason" <Jason dot Diamond at MKG dot com>]

Hi, Mark.

The select attribute doesn't allow attribute value templates. But if all
you're sorting by is the contents of a dynamically specified child element
then you can use the local-name function to match against your variable.

<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>

<xsl:output method="html" indent="no"/>

<xsl:template match="/">
  <xsl:apply-templates/>
</xsl:template>

<xsl:template match="root">
  <xsl:apply-templates select="data">
    <xsl:with-param name="sortexpression" select="sortby"/>
  </xsl:apply-templates>
</xsl:template>

<xsl:template match="data">
  <xsl:param name="sortexpression"/>
  <xsl:apply-templates select="person">
    <xsl:sort select="*[local-name()=$sortexpression]"/>
  </xsl:apply-templates>
</xsl:template>

<xsl:template match="person">
  <xsl:value-of select="name"/>
  <xsl:text>, </xsl:text>
  <xsl:value-of select="age"/>
  <br />
</xsl:template>

</xsl:stylesheet>

All I changed was the select attribute on the sort element.

Hope this helps,
Jason.

> -----Original Message-----
> From: Mark Swardstrom [mailto:mark@nimble.com]
> Sent: Monday, April 02, 2001 10:59 AM
> To: 'XSL-List@lists.mulberrytech.com'
> Subject: [xsl] Dynamic Sorting - Using a variable to 
> determine the sort
> select e xpression
> 
> 
> Hi - I'm trying to dynamically sort a list based on the value 
> of an element
> in my xml document.  Ideally, I'd be able to pass this value 
> to the xsl:sort
> element in the xsl document to determine the sort criteria.  
> In the example
> below, "sortby" could have the value "name" or "age".
> 
> Here's the XML:
> 
> <root>
> 	<sortby>name</sortby>
> 	<data>
> 		<person><name>Bob</name><age>21</age></person>
> 		<person><name>Jim</name><age>63</age></person>
> 		<person><name>Gus</name><age>55</age></person>
> 		<person><name>Van</name><age>18</age></person>
> 		<person><name>Sam</name><age>32</age></person>
> 		<person><name>Don</name><age>39</age></person>
> 		<person><name>Ron</name><age>33</age></person>
> 	</data>
> </root>
> 
> 
> And here's the XSL I tried (it doesn't work, but you'll see 
> what I'm trying
> to do).  I also tried curly braces in the xsl:sort select tag 
> to evaluate
> the sortexpression string as an expression, but no luck.  I understand
> that's not the intended use of the curly brackets, but gave it a shot.
> 
> 
> <xsl:stylesheet version="1.0"
> xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>
> 
> <xsl:output method="html" indent="no"/>
> 
> <xsl:template match="/">
> 	<xsl:apply-templates/>
> </xsl:template>
> 
> <xsl:template match="root">
> 	<xsl:apply-templates select="data">
> 		<xsl:with-param name="sortexpression" select="sortby"/>
> 	</xsl:apply-templates>
> </xsl:template>
> 
> <xsl:template match="data">
> 	<xsl:param name="sortexpression"/>
> 	<xsl:apply-templates select="person">
> 		<xsl:sort select="$sortexpression"/>
> 	</xsl:apply-templates>
> </xsl:template>
> 
> <xsl:template match="person">
> 	<xsl:value-of select="name"/>
> 	<xsl:text>, </xsl:text>
> 	<xsl:value-of select="age"/>
> 	<br />
> </xsl:template>
> 
> </xsl:stylesheet>
> 
> 
> If I can't do this, I find I have to write a bunch of xsl:if 
> clauses and
> that solution doesn't scale and results in bulky code.
> 
> Thanks ahead of time for your thoughts.
> 
> Mark Swardstrom
> Nimble Technology
> 
> 
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> 

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