Re: Dependency Sorting, first of kind

[Francis Norton <francis@xxxxxxxxxxx>]

Hi,

This might be a first cut - it feels like the right approach but has two
problems:

First, I've taken the liberty of simplifying the multiple dependencies
to single dependencies. I think multiple dependencies should be possible
(I assume from the class analogy that they are "and" related) but I
would like to normalise them into a "<depends-on dependee='foo'
dependent='bar'>" element - would that be acceptable, Paul?

Second, and more worrying, I get different results with XT and Saxon, as
shown. Can anyone tell me why? 

Francis.


G:\xmlSchema>type t_.xml
<?xml version="1.0"?>
<data>
        <a name="jaz" depends-on="bar"/>
        <a name="spaz"/>
        <a name="maz" depends-on="spaz"/>
        <a name="foo"/>
        <a name="bar" depends-on="foo"/>
        <a name="baz" depends-on="foo"/>
</data>


G:\xmlSchema>saxon t_.xml t_.xsl

                a=spaz
                a=foo
                a=maz
                a=bar
                a=baz
                a=jazElapsed time: 641 milliseconds

G:\xmlSchema>xt t_.xml t_.xsl
<?xml version="1.0" encoding="utf-8"?>

                a=spaz
                a=foo
                a=maz
                a=bar
                a=jaz

G:\xmlSchema>type t_.xsl
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>

<xsl:template match="/">

  <!-- start by calling untangler with the node-set of roots
    (ie no dependencies) as a parameter -->
  <xsl:call-template name="untangler">
    <xsl:with-param name="this-set"
select="//a/@name[not(../@depends-on)]" />
  </xsl:call-template>

</xsl:template>


<xsl:template name="untangler">

  <!-- this single parameter actually contains a (possibly empty)
node-set -->
  <xsl:param name="this-set" />

  <!-- here we do something with every node in the parameter node-set
-->
  <xsl:for-each select="$this-set">
    a=<xsl:value-of select="." />
  </xsl:for-each>

  <!-- now, if the node-set is not empty, we'll call the template
recursively with
    a new parameter consisting of all the nodes which depended on the
ones in
    *this* node-set -->
  <xsl:if test="$this-set">
    <xsl:call-template name="untangler">

      <!-- the [../@depends-on = $this-set] predicate relies on the
xpath definition
        that one node-set "equals" another if there is a single node
that is in
        both sets -->
      <xsl:with-param name="this-set" select="//a/@name[../@depends-on =
$this-set]" />

    </xsl:call-template>
  </xsl:if>

</xsl:template>

</xsl:stylesheet>


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