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(_at_)excite(_dot_)com
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(_at_)excite(_dot_)com]
Sent: Monday, March 03, 2003 11:02 AM
To: xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com
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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