Am 08.04.2010 um 16:09 schrieb Michael Kay:

It seems to me that you first want to create (or imagine) a graph: in your
example there are arcs k->o, o->p, p->c, a->b, b->c, etc.

Then you want to look for cycles in this graph. If any cycles exist, there
is no solution to your problem.

Thanks Michael, I guess I have to finally understand the graph stuff. I will turn to the example in the 4th edition p.251 ff. for a starter.

Am 08.04.2010 um 16:47 schrieb Imsieke, Gerrit, le-tex:

[... cool, ready-made example ...]

Does that make sense?

If I include<o/>  at the other position, i.e.,
  <seq><k/><f/><z/><o/></seq>,
I receive "Too many nested function calls. May be due to infinite recursion." as expected.

Gerrit, I am at early stages to understand the algorithm. The function counts the maximum number of preceding siblings on any available path and uses this as a sort key. This is some sort of creating a graph, backtracing to the beginning... which is what Michael suggested, isn't it.

Thanks a lot for the most valuable input!

I need a result and the inconsistency report, so the user can fix the input. I will be looking into stopping the infinite recursion somehow.

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

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

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

  <xsl:template match="foo">
    <xsl:copy>
      <xsl:for-each-group select="seq/*" group-by="name(.)" >
        <xsl:sort select="my:sortkey(., ())"/>
        <xsl:element name="{current-grouping-key()}" />
      </xsl:for-each-group>
    </xsl:copy>
  </xsl:template>

</xsl:stylesheet>
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