Re: [xsl] xslt 2.0: grouping flat element structures to make lists

Subject: Re: [xsl] xslt 2.0: grouping flat element structures to make lists
From: JBryant@xxxxxxxxx
Date: Wed, 25 May 2005 14:30:21 -0500
Hi, Derek,

The trick is picking just the bits you want in the list. I took your 
sample lists and made a sample XML file and a stylesheet to demonstrate 
one way to do it (with apply-templates).

Here's the XML file (with non-list elements intermingled with the lists):

<?xml version="1.0" encoding="UTF-8"?>
<lists>
  <par class="Listbegin">Fruit</par>
  <par class="Listitem">Apple</par>
  <par class="Listitem">Orange</par>
  <par class="Listitem">Pear</par>
  <something>thing1</something>
  <something>thing2</something>
  <par class="Listbegin">Colours</par>
  <par class="Listitem">Red</par>
  <par class="Listitem">Green</par>
  <par class="Listitem">Blue</par>
</lists>

And here's the XSL:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>

  <xsl:template match="lists">
    <lists>
      <xsl:for-each-group select="*" 
group-starting-with="par[@class='Listbegin']">
        <list>
          <xsl:apply-templates 
select="current-group()/self::par[@class='Listbegin']|current-group()/self::par[@class='Listitem']"/>
        </list>
      </xsl:for-each-group>
    </lists>
  </xsl:template>

  <xsl:template match="par[@class='Listbegin']">
    <head><xsl:value-of select="."/></head>
  </xsl:template>

  <xsl:template match="par[@class='Listitem']">
    <item><xsl:value-of select="."/></item>
  </xsl:template>

</xsl:stylesheet>

And here's the resulting output:

<?xml version="1.0" encoding="UTF-8"?>
<lists>
  <list>
    <head>Fruit</head>
    <item>Apple</item>
    <item>Orange</item>
    <item>Pear</item>
  </list>
  <list>
    <head>Colours</head>
    <item>Red</item>
    <item>Green</item>
    <item>Blue</item>
  </list>
</lists>

Does that come near the mark or did I misunderstand?

(And this time I remembered to use the self axis. Thanks again to David 
Carlisle.)

Jay Bryant
Bryant Communication Services
(presently consulting at Synergistic Solution Technologies)





"Derek Revill" <derek@xxxxxxxxxxxxxxxxxx> 
05/25/2005 01:07 PM
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Subject
[xsl] xslt 2.0: grouping flat element structures to make lists






Hello

Using XSLT 2.0 (running Saxon 8.4) I am grappling with a pretty standard
grouping issue, attempting to utilize some of XSLT v2 grouping 
possibilities
but with no success (reading the W3C spec and a scan of the archive 
haven't
proved helpful, MK book is on order!).

Mid flow I have:

..
..
<par class="Listbegin">Fruit</par>
<par class="Listitem>Apple</par>
<par class="Listitem>Orange</par>
<par class="Listitem>Pear</par>
<par class="Listbegin">Colours</par>
<par class="Listitem>Red</par>
<par class="Listitem>Green</par>
<par class="Listitem>Blue</par>
..
..

I just need to output

..
..
<list>
                 <head>Fruit</head>
                 <item>Apple</item>
                 <item>Orange</item>
                 <item>Pear</item>
</list>
<list>
                 <head>Colours</head>
                 <item>Red</item>
                 <item>Green</item>
                 <item>Blue</item>
</list>

Note: I'm midway through processing any section when I encounter the <par
class="Listbegin">. The signal that a list has ended can be any
following-sibling that isn't <par class="Listitem>..</par> or the end of 
the
parent element I'm in. Of course, lists don't always come in pairs like
above.

Should I try to match on the <par class="Listbegin"> then scoop-up all
relevant following nodes, which was my strategy up to now? Haven't been 
able
to find a way to scoop-up only the following nodes that are relevant.

Any advice gratefully received. Numerous attempts using for-each-group and
various group-by strategies have been fruitless, probably I just haven't
quite grasped it!

Thanks

Derek Revill

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