RE: [xsl] Recursion and for-each-group (XSLT 2.0)

["Michael Kay" <mike@xxxxxxxxxxxx>]

The problem is here:

  <xsl:template match="indexentry">
    <xsl:variable name="term" select="@term"/>
    <xsl:for-each-group select="//indexentry[@term=$term]" 
group-by="@term">

This means that every time you encounter an indexentry, you are processing
all the indexentry's in the document that have the same term. You are then
grouping these by term, which does nothing useful, because you already
ensured that they all have the same term.

One question about the structure of your data: is it possible to encounter

<indexentry term="dog">
  <indexentry term="leg">
</indexentry>
<indexentry term="table">
  <indexentry term="leg">
</indexentry>

and if so, are the two references to "leg" to be combined, or not? This
doesn't arise in your sample, so I can't tell.

Michael Kay
http://www.saxonica.com/

> -----Original Message-----
> From: JBryant@xxxxxxxxx [mailto:JBryant@xxxxxxxxx] 
> Sent: 05 April 2005 19:34
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject: [xsl] Recursion and for-each-group (XSLT 2.0)
> 
> Hi, all,
> 
> Apologies in advance for a long message. I'm trying to give a 
> complete 
> description of the problem.
> 
> I have defined a set of index entries as nested indexentry 
> elements in my 
> source file. Then, in the XSL, I am trying to use a single 
> template to 
> group the entries at each level. That much is working, but I 
> am getting 
> multiple results. I've tried a number of solutions, but I'm stumped.
> 
> Here's the source file:
> 
> <book>
>   <chapter title="Chapter1">
>     <indexentries>
>       <indexentry term="word1">
>         <indexentry term="word11">
>           <indexentry term="word111">
>             <indexentry term="word1111"/>
>           </indexentry>
>         </indexentry>
>       </indexentry>
>       <indexentry term="word1">
>         <indexentry term="word11">
>           <indexentry term="word112">
>             <indexentry term="word1121"/>
>           </indexentry>
>         </indexentry>
>       </indexentry>
>       <indexentry term="word1">
>         <indexentry term="word12"/>
>       </indexentry>
>       <indexentry term="word2"/>
>     </indexentries>
>   </chapter>
>   <chapter title="Chapter2">
>     <indexentries>
>       <indexentry term="word3">
>         <indexentry term="word31">
>           <indexentry term="word311">
>             <indexentry term="word3111"/>
>           </indexentry>
>         </indexentry>
>       </indexentry>
>       <indexentry term="word3">
>         <indexentry term="word32"/>
>       </indexentry>
>       <indexentry term="word4"/>
>     </indexentries>
>     <topic title="Topic21">
>     <indexentries>
>       <indexentry term="word5">
>         <indexentry term="word51">
>           <indexentry term="word511">
>             <indexentry term="word5111"/>
>           </indexentry>
>         </indexentry>
>       </indexentry>
>       <indexentry term="word5">
>         <indexentry term="word52"/>
>       </indexentry>
>       <indexentry term="word6"/>
>     </indexentries>
>     </topic>
>   </chapter>
> </book>
> 
> Here's my current best shot at a transform:
> 
> <?xml version="1.0" encoding="UTF-8"?>
> <xsl:stylesheet version="2.0" 
> xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>
> 
>   <xsl:template match="/">
>     <xsl:variable name="indexentries">
>       <indexentries>
>         <xsl:for-each select="//indexentries/indexentry">
>           <indexentry term="{@term}" 
> target="{generate-id(ancestor::*[indexentries][1])}">
>             <xsl:copy-of select="indexentry"/>
>           </indexentry>
>         </xsl:for-each>
>       </indexentries>
>     </xsl:variable>
>     <xsl:for-each select="$indexentries">
>       <xsl:apply-templates/>
>     </xsl:for-each>
>   </xsl:template>
>  
>   <xsl:template match="indexentry">
>     <xsl:variable name="term" select="@term"/>
>     <xsl:for-each-group select="//indexentry[@term=$term]" 
> group-by="@term">
>       <indexentry term="{@term}">
>         <xsl:choose>
>           <xsl:when test="indexentry">
>             <xsl:apply-templates select="current-group()/indexentry"/>
>           </xsl:when>
>           <xsl:otherwise>
>             <xsl:attribute name="target" 
> select="ancestor-or-self::*[@target]/@target"/>
>           </xsl:otherwise>
>         </xsl:choose>
>       </indexentry>
>     </xsl:for-each-group>
>   </xsl:template>
> 
> </xsl:stylesheet>
> 
> Here's the output from applying that stylesheet to the source file:
> 
> <?xml version="1.0" encoding="UTF-8"?>
> <indexentry term="word1">
>   <indexentry term="word11">
>     <indexentry term="word111">
>       <indexentry term="word1111" target="d1e3"/>
>     </indexentry>
>     <indexentry term="word112">
>       <indexentry term="word1121" target="d1e3"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word11">
>     <indexentry term="word111">
>       <indexentry term="word1111" target="d1e3"/>
>     </indexentry>
>     <indexentry term="word112">
>       <indexentry term="word1121" target="d1e3"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word12" target="d1e3"/>
> </indexentry>
> <indexentry term="word1">
>   <indexentry term="word11">
>     <indexentry term="word111">
>       <indexentry term="word1111" target="d1e3"/>
>     </indexentry>
>     <indexentry term="word112">
>       <indexentry term="word1121" target="d1e3"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word11">
>     <indexentry term="word111">
>       <indexentry term="word1111" target="d1e3"/>
>     </indexentry>
>     <indexentry term="word112">
>       <indexentry term="word1121" target="d1e3"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word12" target="d1e3"/>
> </indexentry>
> <indexentry term="word1">
>   <indexentry term="word11">
>     <indexentry term="word111">
>       <indexentry term="word1111" target="d1e3"/>
>     </indexentry>
>     <indexentry term="word112">
>       <indexentry term="word1121" target="d1e3"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word11">
>     <indexentry term="word111">
>       <indexentry term="word1111" target="d1e3"/>
>     </indexentry>
>     <indexentry term="word112">
>       <indexentry term="word1121" target="d1e3"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word12" target="d1e3"/>
> </indexentry>
> <indexentry term="word2" target="d1e3"/>
> <indexentry term="word3">
>   <indexentry term="word31">
>     <indexentry term="word311">
>       <indexentry term="word3111" target="d1e38"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word32" target="d1e38"/>
> </indexentry>
> <indexentry term="word3">
>   <indexentry term="word31">
>     <indexentry term="word311">
>       <indexentry term="word3111" target="d1e38"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word32" target="d1e38"/>
> </indexentry>
> <indexentry term="word4" target="d1e38"/>
> <indexentry term="word5">
>   <indexentry term="word51">
>     <indexentry term="word511">
>       <indexentry term="word5111" target="d1e61"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word52" target="d1e61"/>
> </indexentry>
> <indexentry term="word5">
>   <indexentry term="word51">
>     <indexentry term="word511">
>       <indexentry term="word5111" target="d1e61"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word52" target="d1e61"/>
> </indexentry>
> <indexentry term="word6" target="d1e61"/>
> 
> And here's what I am aiming for:
> 
> <?xml version="1.0" encoding="UTF-8"?>
> <indexentry term="word1">
>   <indexentry term="word11">
>     <indexentry term="word111">
>       <indexentry term="word1111" target="d1e3"/>
>     </indexentry>
>     <indexentry term="word112">
>       <indexentry term="word1121" target="d1e3"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word12" target="d1e3"/>
> </indexentry>
> <indexentry term="word2" target="d1e3"/>
> <indexentry term="word3">
>   <indexentry term="word31">
>     <indexentry term="word311">
>       <indexentry term="word3111" target="d1e38"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word32" target="d1e38"/>
> </indexentry>
> <indexentry term="word4" target="d1e38"/>
> <indexentry term="word5">
>   <indexentry term="word51">
>     <indexentry term="word511">
>       <indexentry term="word5111" target="d1e61"/>
>     </indexentry>
>   </indexentry>
>   <indexentry term="word52" target="d1e61"/>
> </indexentry>
> <indexentry term="word6" target="d1e61"/>
> 
> As you can see, multiple nodes are appearing in the output 
> tree. I'm using 
> Saxon 8.3, but I very much doubt the processor is the issue.
> 
> Thanks much.
> 
> Jay Bryant
> Bryant Communication Services
> (presently consulting at Synergistic Solution Technologies)