Re: [xsl] Grouping a sequence of elements in different ways

On 21.05.2010 23:09, Peter Desjardins wrote:

Can anyone point me to an example of that sort of stylesheet? One that
performs several types of grouping during the same pass over a
sequence of elements? Here's an example of the code I'm using. Both of
the grouping operations will work if I use them alone.

<xsl:template match = "body/div">
     <xsl:for-each-group select = "current-group()" group-adjacent =
"name()='p' and @class='bulletedlist'">
         <xsl:apply-templates select = "." mode = "itemizedlist" />
     </xsl:for-each-group>
     <!-- How do I perform both of these grouping operations at the
same time? -->
     <xsl:for-each-group select = "*" group-starting-with = "p[@class='head1']">
         <xsl:apply-templates select="." mode="group-level-one"/>
     </xsl:for-each-group>
</xsl:template>

It's ok to group in a single pass, but not at the same time. You should use nested groupings. Section hierarchy (group-starting-with) comes first, then the sections' contents will be grouped according to whether they are list items or not.

Here's a sample XHTML body as input:

===========8<-----------------------
<?xml version="1.0" encoding="utf-8"?>
<body>
<p>pre</p>
<p class="bulletedlist">one</p>
<p class="bulletedlist">two</p>
<p class="bulletedlist">three</p>
<h5>This is h5</h5>
<h4>Attribution</h4>
<p>...</p>
<h3>Preface</h3>
<p class="orderedlist">1. one</p>
<p class="orderedlist">2. two</p>
<p class="bulletedlist">one</p>
<p class="bulletedlist">two</p>
<p class="bulletedlist">three</p>
<p class="orderedlist">3. three</p>
<h4>[Preface]</h4>
<p>...</p>
<h3>INTRODUCTION</h3>
<p>...</p>
<p class="bulletedlist">one</p>
<p class="bulletedlist">two</p>
<h5>baz</h5>
<p>foo</p>
</body>
===========8<-----------------------

Here's a stylesheet to process the input

===========8<-----------------------
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
  xmlns:xs="http://www.w3.org/2001/XMLSchema";
  xmlns:my="my"
  version="2.0"
  exclude-result-prefixes="my xs"
  >

<xsl:output method="xml" indent="yes" />

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

  <xsl:template match="body">
    <xsl:copy>
      <xsl:sequence select="my:hierarchize(*)" />
    </xsl:copy>
  </xsl:template>

  <xsl:function name="my:hierarchize" as="element(*)*">
    <xsl:param name="nodes" as="element(*)*" />
    <xsl:for-each-group select="$nodes"
        group-starting-with="*[my:isHeading(.)][
                                my:hlevel(.) le min(
                                  (
                                    for $ph in (
                                      preceding-sibling::*
                                      intersect $nodes[my:isHeading(.)]
                                    )
                                    return my:hlevel($ph),
                                    6
                                  )
                                )
                              ]">
      <xsl:choose>
        <xsl:when test="my:isHeading(.)">
          <div class="level{my:hlevel(.)}">
            <title>
<!-- please note that node() are all nodes of the context
     item, which is the group's first element, i.e., the
     heading: -->
              <xsl:copy-of select="node()" />
            </title>
<!-- will be called recursively: -->
            <xsl:sequence
              select="my:hierarchize(current-group()[position() gt 1])" />
          </div>
        </xsl:when>
        <xsl:otherwise>
<!-- until no heading is in the nodes to process.
     Then start processing the lists: -->
          <xsl:sequence select="my:listify(current-group())" />
        </xsl:otherwise>
      </xsl:choose>
    </xsl:for-each-group>
  </xsl:function>

  <xsl:function name="my:listify" as="element(*)*">
    <xsl:param name="nodes" as="element(*)*" />
    <xsl:for-each-group select="$nodes"
        group-adjacent="boolean(self::p[@class='bulletedlist'])">
      <xsl:choose>
        <xsl:when test="current-grouping-key()">
          <itemizedlist>
            <xsl:sequence select="current-group()" />
          </itemizedlist>
        </xsl:when>
        <xsl:otherwise>
          <xsl:sequence select="current-group()" />
        </xsl:otherwise>
      </xsl:choose>
    </xsl:for-each-group>
  </xsl:function>

  <xsl:function name="my:isHeading" as="xs:boolean">
    <xsl:param name="elt" as="element(*)" />
    <xsl:value-of select="matches(local-name($elt), '^h\d$')" />
  </xsl:function>

<xsl:function name="my:hlevel" as="xs:double"> <xsl:param name="elt" as="element(*)" /> <xsl:value-of select="number(replace(local-name($elt), '^h(\d)$', '$1'))" /> </xsl:function>

</xsl:stylesheet>
===========8<-----------------------

Gerrit

<- Previous	Index	Next ->
RE: [xsl] Grouping a sequence of el, Michael Kay	Thread	Re: [xsl] Grouping a sequence of el, Peter Desjardins
RE: [xsl] Grouping a sequence of el, Michael Kay	Date	[xsl] Two recommendations: (1) Call, Costello, Roger L.
	Month

<-prev [Thread] next->	<-prev [Date] next->
Month Index \| List Home

Re: [xsl] Grouping a sequence of elements in different ways in the same stylesheet