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RE: [xsl] graph-traversal query


Subject: RE: [xsl] graph-traversal query
From: "Michael Kay" <mike@xxxxxxxxxxxx>
Date: Fri, 28 Jan 2005 15:25:13 -0000

Ignoring the stuff about case-independence, define a key on the identifier

<xsl:key name="k" match="DEFCONCEPT" use="@name"/>

Find the logical parent using the key function:

key("k", PARENT/CONCEPT/@name)

or the grandparent by doing it twice:

key("k", PARENT/CONCEPT/@name) / key("k", PARENT/CONCEPT/@name)

That's XPath 2.0, in 1.0 you write 

key("k", key("k", PARENT/CONCEPT/@name)/PARENT/CONCEPT/@name)

Since your data (unusually) represents relationships in both directions, you
can also use the key to find the children

key("k", CHILD/CONCEPT/@name)

or grandchildren:

key("k", CHILD/CONCEPT/@name) / key("k", CHILD/CONCEPT/@name)

Michael Kay
http://www.saxonica.com/


> -----Original Message-----
> From: RQamar [mailto:qamar_rahil@xxxxxxxxxxx] 
> Sent: 28 January 2005 14:27
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject: [xsl] graph-traversal query
> 
> Hi
> 
> This is a question I asked earlier on the forum and was advised by 
> Wendell to send it as a seperate query so I could get feedback from a 
> wider audience.
> 
> I'm educating myself on XSLT and XPath but until the two books Ive 
> recently ordered arrive, I'd need some help from the experts 
> to help me 
> proceed.
> 
> My query is thus:
> 
> > Im finding the dynamic assigning and traversing process in 
> XSL quite 
> > confusing. Is there a logical way of  traversing through a tree to 
> > determine the grandchild of an element albeit indirectly. So I know 
> > that my XML file is as below
> >
> > -----------------------
> > <DEFCONCEPT id="10180" name="Car">
> >        <PARENT>
> >            <CONCEPT name="Automobile" ref="10181"/>
> >        </PARENT>
> >        <CHILD>
> >            <CONCEPT name="Toyota" ref="10235"/>
> >        </CHILD>
> > </DEFCONCEPT >
> > <DEFCONCEPT id="10235" name="Toyota">
> >        <PARENT>
> >            <CONCEPT name="Car" ref="10180"/>
> >        </PARENT>
> >        <CHILD>
> >            <CONCEPT name="Corolla" ref="10279"/>
> >        </CHILD>
> > </DEFCONCEPT >
> > <DEFCONCEPT id="10279" name="Corolla">
> >        <PARENT>
> >            <CONCEPT name="Toyota" ref="10235"/>
> >        </PARENT>
> > </DEFCONCEPT >
> > -----------------------
> > and I want to reach the <DEFCONCEPT name="Corolla"> from the node 
> > <DEFCONCEPT name="Car"> because I have a query to determine the 
> > existence of a kind_of  Car 'Corolla' irrespective of the 
> case (upper 
> > or lower) in which it has been written and where in the 
> hierarchy it 
> > exists. How will it be possible using XSLT?
> 
> 
> Thanks
> Rahil


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