RE: [xsl] xsl:variable and position question and experience

["Passin, Tom" <tpassin@xxxxxxxxxxxx>]

This message, and several others posted today, are __NOT__ from me, even
though my name is in the From: header.

The are actually from 

ds5j@xxxxxxxxxx

and I would appreciate it if this individual would correct his/her
postings.

Tom P [the real Tom Passin]

> -----Original Message-----
> From: Passin, Tom [mailto:ds5j@xxxxxxxxxx] 
> Sent: Monday, March 03, 2003 11:02 AM
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject: [xsl] xsl:variable and position question and experience
> 
> 
> 
> 
> Hi,
>      Extending on Jenny Tennison example of using document 
> example to compare file elements I ran into some interesting 
> behavior regarding variables as I tried to compare elements 
> in the same position in 2 files. 
> 
> Please see the examples and questions below
> 
>      Example XML Files:
>      
>      File Containing references to other Files
>      <files>
>           <file href="file1.xml" /> 
>           <file href="file2.xml" /> 
>      </files>
>      
>      file1.xml :
>      <file>
>      <Products>
>      <Product name="1"/>
>      <Product name="2"/>
>      <Product name="3"/>
>      </Products>
>      </file>
> 
>      file2.xml :
>      <file>
>      <Products>
>      <Product name="1"/>
>      <Product name="20"/>
>      <Product name="3"/>
>      </Products>
>      </file>
> 
>      In the stylesheet the following global variables are declared:
>      <xsl:variable name="file1" 
> select="document(/files/file[1]/@href, /)" />
>      <xsl:variable name="file2" 
> select="document(/files/file[2]/@href, /)" />
> 
>      Later inside template matches or for-each loops I try to 
> use these variables to compare elements by position(product 
> elements). I am unable to do a value-of on them.
> 
>      Example:
>      1) Inside a template match on *, or $file1//Product the 
> following strangeness occurs:
> 
>      <xsl:value-of select="$file1//Product[1]/@name" /> 
> prints the name of the product
>      but <xsl:value-of select="$file1//Product[2]/@name"/> 
> does not print anything.
> 
> It seems test clauses are able to access the values in the 
> variables but value-of can't.
>      Example:
>      2) Inside a similar template or foreach
> 
>      The following test is true when the second product in 
> file2 is different. It seems the test in the match is true 
> although the Product[1] in both files are the same. It is 
> somehow matching the second products in the 2 files. Even so 
> if I try to print the second product name attribute it does not work.
> 
>      <xsl:when test="$file1//Product[1]/@name != 
> $file2//Product[1]/@name">
>           CHANGE DETECTED     
>           <xsl:if test="$file2//Product[1]/@name='20'">20</xsl:if>
>           <!-- the test can access the second files second product-->
>           <xsl:value-of select="$file2//Product[2]/@name" /> 
>           <!-- the value of prints nothing proving it cannot 
> access the second file's second product-->
>      </xsl:when>
> 
>      
>      If Product[1] is somehow iterating through the Product 
> nodes that is cool. But why can't I access the value of 
> attributes in a value-of statement when xsl:when or xsl:if 
> test clauses can?
>      
> 
> xsl:value of can access elements by position if the variable 
> points to the specific element in the file
>      Example:     
>      3)     If a variable pointing to the product node is 
> created then it is possible to access the Product attributes 
> using positions. It seems positions only work on the element 
> stored in the variable and not on subelements of elements in 
> a variable
> 
>      The following works:
>      <xsl:variable name="product1" 
> select="document(/files/file[2]/@href, /)//Product" /> 
>      <xsl:value-of select="$product1[2]//@name" /> 
>      <!-- the second product in file can be accessed this way-->
> 
>      but I don't understand why. It is in convenient to have 
> to create many variables for a file to access each element 
> that needs to be accessed by position.
> 
> 
>      If you can explain why these things work the way they do 
> please let me know or if are these idiosyncrasies are bugs?
> 
>      Also I have tried this in xalan and saxon and get the 
> same behavior, so I assume this is not a bug but a lack of 
> understanding on my part.
> 
> thanks
> 
> DS
> 
> 
> 
> 
> 
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