Re: [xsl] 1) Position of keyed element, 2) Determining unique attribute values

[Timothy Lebo <timothy.lebo@xxxxxxxxxxx>]

Considering the cost, I would rather the pre-pass that I was trying  
to avoid.

Is it possible to place an <xsl:attribute> as a child of a <xsl:copy- 
of select="."> to augment the element with my new ID? Or do I need to  
enumerate xsl:element/xsl:attribute for all elements and attributes  
possible in my input?

Thanks,
Tim

On Jan 12, 2006, at 6:49 AM, Michael Kay wrote:

> position() doesn't give you the position of a node in the input  
> tree, it
> gives you its position within whatever sequence of nodes that you are
> processing at the time. For the position in the input tree, use  
> xsl:number,
> or something like count(preceding::object). This is potentially quite
> expensive, if performance is an issue you might be better off to do a
> pre-pass copying the tree and allocating numbers as you go, storing  
> the
> numbers in a new attribute.
>
> In XSLT 2.0 you can easily get the distinct attribute names using
> distinct-values(//attribute/@name).
>
> Michael Kay
> http://www.saxonica.com/
>
> > -----Original Message-----
> > From: Timothy Lebo [mailto:timothy.lebo@xxxxxxxxxxx]
> > Sent: 12 January 2006 11:41
> > To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> > Subject: [xsl] 1) Position of keyed element, 2) Determining
> > unique attribute values
> >
> > Greetings,
> >
> > In short, I am attempting to transfom something that looks like:
> > <?xml version="1.0" encoding="UTF-8"?>
> > <root>
> > <object id="a">
> >     <attribute name="color" value="red"/>
> > </object>
> > <object id="b">
> >      <attribute name="size" value="big"/>
> > </object>
> > <object id="c">
> >      <attribute name="size" value="small"/>
> >      <attribute name="color" value="purple"/>
> > </object>
> > <link fromobject="c" toobject="b"/>
> > </root>
> >
> > into:
> > <?xml version="1.0" encoding="UTF-8"?>
> > <output>
> >    <thing id="1"/>
> >    <thing id="2"/>
> >    <thing id="3"/>
> >    <attributes name="color">
> >       <attribute idref="1" value="red"/>
> >       <attribute idref="3" value="purple"/>
> >    </attributes>
> >    <attributes name="size">
> >       <attribute idref="2" value="big"/>
> >       <attribute idref="3" value="small"/>
> > </attributes>
> > <relation fromthing="3" tothing="2"/>
> > </output>
> >
> > My solution, listed below, has two problems:
> >
> > 1) Obtaining the positional information of elements in the input tree
> > from different context nodes.
> >
> > 2) Unable to determine all unique values of //attribute/@name to  
> > group
> > into the attributes element. (These would then be processed with the
> > solution to #1)
> >
> > The the 'thing' IDs in the output MUST be non-negative integers, so
> > generate-id is out. I thought that it would be nice (and aesthetic,
> > IMHO) to use the position of the 'object's to assign IDs for the
> > 'thing's. However, when I try to obtain positional information from
> > the input tree with position(), I get the location of the node in the
> > result node set of the xpath that selects the nodes, which is always
> > "1".
> >
> > Any solutions with XSLT 2.0 constructs would be much appreciated. I
> > haven't followed the developments within the last three years and am
> > having some difficulty appreciating its full benefits.
> >
> > Highest regards,
> > Tim Lebo
> >
> > XSLT Processor: saxonb8.6.1
> >
> >
> > My current attempt is:
> >
> > <?xml version="1.0"?>
> > <xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
> > version="2.0">
> > <xsl:output method="xml" indent="yes"/>
> >
> > <xsl:key name="objects" match="object" use="@id"/>
> >
> > <xsl:template match="/">
> > <xsl:element name="output">
> >     <xsl:apply-templates select="//object"/>
> >     <xsl:apply-templates select="//object" mode="attributes"/>
> >     <xsl:apply-templates select="//link"/>
> > </xsl:element>
> > </xsl:template>
> >
> > <xsl:template match="object">
> > <xsl:element name="thing">
> >     <xsl:attribute name="id" select="position()"/>
> > </xsl:element>
> > </xsl:template>
> >
> > <xsl:template match="object" mode="attributes">
> > <xsl:element name="attributes">
> >     <xsl:attribute name="name" select="'WRONG: attribute elements
> > should be grouped by attribute/@name, not by object/@id'"/>
> >     <xsl:apply-templates select="attribute">
> >       <xsl:with-param name="id" select="position()"/>
> >     </xsl:apply-templates>
> > </xsl:element>
> > </xsl:template>
> >
> > <xsl:template match="attribute">
> > <xsl:param name="id"/>
> > <xsl:element name="attribute">
> >     <xsl:attribute name="idref" select="$id"/>
> >     <xsl:attribute name="{@name}" select="@value"/>
> > </xsl:element>
> > </xsl:template>
> >
> > <xsl:template match="link">
> > <xsl:variable name="toobjectID" select="@toobject"/>
> > <xsl:element name="relation">
> >     <xsl:attribute name="fromthing"
> > select="key('objects',@fromobj
> > ect)/position()"/>
> >     <xsl:attribute name="tothing"
> > select="//object[@id=$toobjectID]/position()"/>
> >     <xsl:attribute name="NB" select="'WRONG: ids should be  
> > position of
> > input object elmenents (3,2)'"/>
> > </xsl:element>
> > </xsl:template>
> >
> > </xsl:transform>
> >
> > and the output is:
> > <?xml version="1.0" encoding="UTF-8"?>
> > <output>
> >    <thing id="1"/>
> >    <thing id="2"/>
> >    <thing id="3"/>
> >    <attributes name="WRONG: attribute elements should be grouped by
> > attribute/@name , not by object/@id">
> >       <attribute idref="1" color="red"/>
> >    </attributes>
> >    <attributes name="WRONG: attribute elements should be grouped by
> > attribute/@name , not by object/@id">
> >       <attribute idref="2" size="big"/>
> >    </attributes>
> >    <attributes name="WRONG: attribute elements should be grouped by
> > attribute/@name , not by object/@id">
> >       <attribute idref="3" size="small"/>
> >       <attribute idref="3" color="purple"/>
> >    </attributes>
> >    <relation fromthing="1" tothing="1"
> >              NB="WRONG: ids should be position of input object
> > elmenents (3,2)"/>
> > </output>