[xsl] Re: filtering problem

[Adrian Herscu <adrian.herscu@xxxxxxxxx>]

Hi Michael,

thanks for the help :)

I tried to apply your idea on my template (written in XSL 1.0 + Xalan 
Extensions); here is what I got:

The input xml:
<?xml version="1.0" encoding="UTF-8"?>
<procedure name="RunSomething">
  <command src="10" />
  <command src="11" />
  <command src="12" />
  <command src="13" />
  <call name="DoFoo">
    <command src="20" />
    <command src="21" />
    <command src="22" />
    <call name="MakeFoo">
      <command src="30" />
      <command src="31" failed="true()" />
      <command src="32" />
    </call>
    <command src="24" />
    <command src="25" failed="true()" />
    <call name="WriteFoo">
      <command src="40" />
      <command src="41" failed="true()" />
      <command src="42" />
    </call>
    <command src="26" />
  </call>
</procedure>

The XSL:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"; 
xmlns:xalan="http://xml.apache.org/xalan";
  exclude-result-prefixes="xalan">

  <xsl:output method="xml" indent="yes" encoding="UTF-8"
    media-type="text/xml" xalan:indent-amount="2" />

  <xsl:strip-space elements="*" />

  <xsl:variable name="firstFailure" 
select="(//command[@failed=true()])[1]" />
  <xsl:variable name="pathToFirstFailure"
    select="xalan:nodeset($firstFailure)/ancestor-or-self::*" />

  <xsl:template match="command[@failed=true()]">
    <failing-command src="{@src}" />
  </xsl:template>

  <xsl:template
    match="*[xalan:intersection(node(), 
xalan:nodeset($pathToFirstFailure))]">
    <xsl:copy>
      <xsl:copy-of select="@*" />
      <xsl:apply-templates />
    </xsl:copy>
  </xsl:template>

  <xsl:template match="*" />

</xsl:stylesheet>

The output:
<?xml version="1.0" encoding="UTF-8"?>
<procedure name="RunSomething">
  <call name="DoFoo">
    <call name="MakeFoo">
      <failing-command src="31" />
    </call>
    <failing-command src="25" />
  </call>
</procedure>

My problem is with the <failing-command src="25" /> element; it should 
not be generated. How do I filter it out?

Thanks,
Adrian.

On 6/17/2010 12:15 PM, Michael Kay wrote:
> Perhaps something like this:
>
> <xsl:variable name="firstFailure"
> select="(//command[@failed='true()])[1]"/>
>
> <xsl:variable name="pathToFirstFailure"
> select="$firstFailure/ancestor-or-self::*"/>
>
> <xsl:template match="*[. intersect $pathToFirstFailure]">
> <xsl:copy>
> <xsl:copy-of select="@*"/>
> <xsl:apply-templates/>
> </xsl:copy>
> </xsl:template>
>
> <xsl:template match="*"/>
>
> You don't see this coding pattern very often, but I sometimes find it
> quite useful: select the "interesting" nodes in a global variable, and
> then use this global variable in a match pattern to steer which template
> rule is used to process which nodes. In XSLT 2.1 you will be able to
> replace the match pattern above with
>
> match="$pathToFirstFailure"
>
> Michael Kay
> Saxonica
>
> On 17/06/2010 09:54, Adrian Herscu wrote:
> > Hi all,
> >
> > Consider the following input XML file:
> >
> > <?xml version="1.0" encoding="UTF-8"?>
> > <batch name="level1">
> > <command src="1" />
> > <command src="2" failed="true()" />
> > <command src="3" />
> > <command src="4" failed="true()" />
> > <batch name="level2">
> > <command src="10" />
> > <command src="11" failed="true()" />
> > <command src="12" />
> > <batch name="level3">
> > <command src="20" />
> > <command src="21" failed="true()" />
> > <command src="22" />
> > </batch>
> > <command src="30" />
> > <command src="31" failed="true()" />
> > <command src="32" />
> > </batch>
> > </batch>
> >
> > I need an XSL transformation that scans the top-level batch until it
> > finds a command marked as failed, no matter at which internal
> > batch-level it is, preserving the batch level on the report.
> >
> > Currently, I have this XSL:
> >
> > <?xml version="1.0" encoding="UTF-8"?>
> > <xsl:stylesheet version="1.0"
> > xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
> > xmlns:xalan="http://xml.apache.org/xalan";>
> >
> > <xsl:output method="xml" indent="yes" encoding="UTF-8"
> > media-type="text/xml" xalan:indent-amount="2" />
> >
> > <xsl:strip-space elements="*" />
> >
> > <xsl:template match="/">
> > <xsl:apply-templates />
> > </xsl:template>
> >
> > <!--
> > FIXME: batches are matched even though there is a prior failed
> > command or batch containing a failed command
> > -->
> > <xsl:template match="batch">
> > <batch name="{@name}">
> > <xsl:apply-templates />
> > </batch>
> > </xsl:template>
> >
> > <!-- match only the first failing command -->
> > <xsl:template match="command[@failed=true()][1]">
> > <failed-command src="{@src}" />
> > </xsl:template>
> > </xsl:stylesheet>
> >
> > which generates:
> >
> > <?xml version="1.0" encoding="UTF-8"?>
> > <batch xmlns:xalan="http://xml.apache.org/xalan"; name="level1">
> > <failed-command src="2" />
> > <batch name="level2">
> > <failed-command src="11" />
> > <batch name="level3">
> > <failed-command src="21" />
> > </batch>
> > </batch>
> > </batch>
> >
> > instead of:
> >
> > <?xml version="1.0" encoding="UTF-8"?>
> > <batch xmlns:xalan="http://xml.apache.org/xalan"; name="level1">
> > <failed-command src="2" />
> > </batch>
> >
> > Another example -- if only command[@src='21'] is marked failed, then
> > the generated output should be:
> >
> > <?xml version="1.0" encoding="UTF-8"?>
> > <batch name="level1">
> > <batch name="level2">
> > <batch name="level3">
> > <failed-command src="21" />
> > </batch>
> > </batch>
> > </batch>
> >
> > Thanks for your help,
> > Adrian.