RE: [xsl] Recursive positional grouping (was xsl digest...)

Subject: RE: [xsl] Recursive positional grouping (was xsl digest...)
From: "Michael Kay" <mike@xxxxxxxxxxxx>
Date: Wed, 4 Apr 2007 10:51:28 +0100
> Thanks. (The hint in XSLT 2.0, 3Ed, p298 is wrong then).

Good catch.
> 
> Using
> <xsl:template match="*[starts-with(name(),'h')]">
>   <xsl:variable name="tag" 
> select="translate(name(current()),'1234','2345')"/>
>   <xsl:message>
>   Match on <xsl:value-of select="name()"/>
>   Population is <xsl:value-of select="count(current-group())"/>
>   next is <xsl:value-of select="$tag"/>
>   </xsl:message>
>   <section level="{substring-after(name(),'h')}">
>     <head><xsl:apply-templates/></head>
>     <xsl:for-each-group select="current-group() except ."
>       group-starting-with="*[name() = $tag]">
>       <xsl:apply-templates select="current-group()"/>
>     </xsl:for-each-group>
>   </section>
> </xsl:template>
> 
> Still doesn't hack it though.
> It seems to handle the lower levels,
> but not something like
> h3
> h3
> h2
> 

I think your problem is that 

<xsl:apply-templates select="current-group()"/>

is processing all the elements in a group, not only the next-level headings
- so the paragraphs are output at every level.

I think this kind of recursive grouping works best if you use a named
template that is passed the contents of a group as a parameter. Try
something like this:

<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
  xmlns:xs="http://www.w3.org/2001/XMLSchema";>
<xsl:output indent="yes"/>

<xsl:template name="group">
  <xsl:param name="pop" as="element()*"/>
  <xsl:param name="level" as="xs:integer" />
  <xsl:variable name="key" as="xs:string" select="concat('h', $level)"/>
    <xsl:for-each-group select="$pop" group-starting-with="*[name() eq
$key]">
      <xsl:choose>
        <xsl:when test="starts-with(name(.), 'h')">
          <section level="{$level}">     
            <head><xsl:apply-templates select="current-group()[1]"/></head>
            <xsl:call-template name="group">
              <xsl:with-param name="pop" select="remove(current-group(),
1)"/>
              <xsl:with-param name="level" select="$level + 1"/>
            </xsl:call-template>
          </section> 
        </xsl:when>
        <xsl:otherwise>
          <xsl:copy-of select="current-group()"/>
        </xsl:otherwise>
      </xsl:choose>    
    </xsl:for-each-group>
</xsl:template>

<xsl:template match="/">
  <doc>
    <xsl:call-template name="group">
      <xsl:with-param name="pop" select="body/*"/>
      <xsl:with-param name="level" select="1"/>
    </xsl:call-template>
  </doc>
</xsl:template>


</xsl:stylesheet>

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