Inconsistency in nodeset test? - xslt

I have an XML with top-level elements in this vein:
<chapter template="one"/>
<chapter template="two"/>
<chapter template="one"/>
<chapter template="one"/>
<chapter template="two"/>
<chapter template="one"/>
I'm processing these elements by looping through them with a choose statement:
<xsl:variable name="layout" select="#template"/>
<xsl:choose>
<xsl:when test="contains($layout, 'one')">
<xsl:call-template name="processChapterOne"/>
</xsl:when>
<xsl:when test="contains($layout, 'two')">
<xsl:call-template name="processChaptertwo"/>
</xsl:when>
<xsl:otherwise/>
</xsl:choose>
This works correctly. But now I'm trying to do some conditional processing, so I'm trying to find the first chapter in the list:
<xsl:when test="count(preceding-sibling::*[($layout = 'one')]) = '0'">
<xsl:call-template name="processChapterOne"/>
</xsl:when>
Here's when things get weird. My test never becomes true: the value of count(...) is 4 for the first chapter in the list, and increments from there. It looks like it counts all of the top-level elements, and not just the ones named 'chapter'.
When I change the code to this:
<xsl:when test="count(preceding-sibling::*[(#template = 'one')]) = '0'">
<xsl:call-template name="processChapterOne"/>
</xsl:when>
it works correctly. So I've replaced a variable with a direct reference. I can't figure out why this would make a difference. What could cause this?

The not working and working cases are actually very different:
Not working: In preceding-sibling::*[$layout = 'one'], $layout is always the same value of one as it was when originally set in the <xsl:variable name="layout" select="#template"/> statement.
Working: In preceding-sibling::*[#template = 'one'], #template varies per the #template attribute value of the varying preceding-sibling context nodes.

*[(#template = 'one')]
Above means: count all nodes where attribute template equals the text one.
*[($layout = 'one')]
Above means: count all nodes where variable layout equals the text one.
I think with the question you raised $layout is not filled with the text one, but it does a xsl:call-template. Maybe something is going wrong here?
Besides that if you don't want to count all nodes but only the chapter nodes. Do this:
chapter[($layout = 'one')]
chapter[(#template = 'one')]

Related

Looping through an xpath getting the right iteration each time in xslt 2

I have a condition where I need to loop atleast once and so I have the following xsl code. However, this doesnt work as it always gets the last iterations value. How can I tweak this so it gets the right iteration on each loop?
<xsl:variable name='count0'>
<xsl:choose>
<xsl:when test='count($_BoolCheck/BoolCheck[1]/CheckBoolType) = 0'>
<xsl:value-of select="1"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select='count($_BoolCheck/BoolCheck[1]/CheckBoolType)'/>
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:for-each select="1 to $count0">
<xsl:variable name='_LoopVar_2_0' select='$_BoolCheck/BoolCheck[1]/CheckBoolType[position()=$count0]'/>
<e>
<xsl:attribute name="n">ValueIsTrue</xsl:attribute>
<xsl:attribute name="m">f</xsl:attribute>
<xsl:attribute name="d">f</xsl:attribute>
<xsl:if test="(ctvf:isTrue($_LoopVar_2_0/CheckBoolType[1]))">
<xsl:value-of select=""Value True""/>
</xsl:if>
</e>
</xsl:for-each>
The xml file is as follows:
<BoolCheck>
<CheckBoolType>true</CheckBoolType>
<CheckBoolType>false</CheckBoolType>
<CheckBoolType>1</CheckBoolType>
<CheckBoolType>0</CheckBoolType>
<CheckBoolType>True</CheckBoolType>
<CheckBoolType>False</CheckBoolType>
<CheckBoolType>TRUE</CheckBoolType>
<CheckBoolType>FALSE</CheckBoolType>
</BoolCheck>
In this case I need to iterate through each iteration of CheckBoolType and produce a corresponding number of values. However, in the above example if there were no CheckBoolType iterations I would still like the iterations to enter the for-each loop atleast once. i hope that clarifies it a little more.
First observation: your declaration of $count0 can be replaced by
<xsl:variable name="temp" select="count($_BoolCheck/BoolCheck[1]/CheckBoolType)"/>
<xsl:variable name="count0" select="if ($temp=0) then 1 else $temp"/>
(Sorry if that seems irrelevant, but my first step in debugging code is always to simplify it. It makes the bugs much easier to find).
When you do this you can safely replace the predicate [position()=$count0] by [$count0], because $count0 is now an integer rather than a document node. (Even better, declare it as an integer using as='xs:integer' on the xsl:variable declaration.)
But hang on, $count0 is the number of elements being processed, so CheckBoolType[$count] will always select the last one. That's surely not what you want.
This brings us to another bug in your code. The value of the variable $_LoopVar_2_0 is an element node named CheckBoolType. The expression $_LoopVar_2_0/CheckBoolType[1] is looking for children of this element that are also named CheckBoolType. There are no such children, so the expression selects an empty sequence, so the boolean test is always false.
At this stage I would like to show you some correct code to achieve your desired output. Unfortunately you haven't shown us the desired output. I can't reverse engineer the requirement from (a) your incorrect code, and (b) your prose description of the algorithm you are trying to implement.

Change text of elements identified by dynamic XPath

I have an XML with 2 XML fragments, 1st one is a fragment where the new values must be applied (which can have pretty complex elements) like
... some static parents
<a:element1>
<a:subelement tag="someString">
<a:s1>a</a:s1>
</a:subelement>
</a:element1>
<a:element2>b</a:element2>
<a:element3>c</a:element3>
... lots of other elements like the above ones
and 2nd fragment that has XPaths generated from the first XML and a new value, like
<field>
<xpath>/Parent/element1/subelement[#tag="someString"]/s1</xpath>
<newValue>1</newValue>
</field>
<field>
<xpath>/Parent/element2</xpath>
<newValue>2</newValue>
</field>
We might not have new values to apply for all the elements in the first fragment.
I'm struggling to make an XSLT transformation that should apply the new values to the places indicated by the XPaths.
The output should be:
... some static parents
<a:element1>
<a:subelement tag="someString">
<a:s1>1</a:s1>
</a:subelement>
</a:element1>
<a:element2>2</a:element2>
... lots of other elements like the above ones
I have access to xalan:evaluate to evaluate the dynamic xpath. I'm trying different solutions, I will write them here when they will start to make sense.
Any ideas of approaches are well received. Thanks
Oki, I found out how, and I will write the answer here maybe someone sometime will need this:
<xsl:template match="/">
<!-- static parents -->
<a:Root>
<xsl:apply-templates select="/a:Root/a:Parent" />
</a:Root>
</xsl:template>
<xsl:template match="#*|*|text()">
<xsl:variable name="x" select="generate-id(../.)" />
<xsl:variable name="y" select="//field[generate-id(xalan:evaluate(xpath)) = $x]" />
<xsl:choose>
<xsl:when test="$y">
<xsl:value-of select="$y/newValue" />
</xsl:when>
<xsl:otherwise>
<xsl:copy>
<xsl:apply-templates select="#*|*|text()" />
</xsl:copy>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
And to explain the transformation:
I'm writing down part that is static and then call apply-templates on the fragment I'm interested in, that has a liquid structure.
Then I'm using a slightly modified identity transformation that copies everything from source to target (starting from the /a:Root/a:Parent fragment), except when we position ourselves on the text I'm interested in changing.
The text() I'm interested in will have as parent (../.) the element referred by an xpath string found in the second fragment. Variable x means, in the context of the when, this element.
Variable y finds a field element that has as child an xpath element that if evaluated using xalan will refer to the same element that the x variable relates to.
Now I used generate-id() in order to compare the physical elements, otherwise it would have compared by the toString of the element (which is wrong). If variable y doesn't exist, it means that I have no xpath element for this element that could have changed, and I'm leaving it alone. If the y variable exists, I can get from it the newValue and I'm currently positioned on the element which text I want to update.

XSLT1.0: Multiple values in choose-when in the right part of equation?

Is there any way to put more then one value in the right part of equation?
<xsl:choose>
<xsl:when test="Properties/LabeledProperty[Label='Category Code']/Value = 600,605,610">
This code above returns:
XPath error : Invalid expression
Properties/LabeledProperty[Label='Category Code']/Value = 600,605,610
^
compilation error: file adsml2adpay.xsl line 107 element when
The reason I don't want to use 'OR' is because there are around 20 numbers should be in the right part for each 'when' test.
<xsl:stylesheet
version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:config="http://tempuri.org/config"
exclude-result-prefixes="config"
>
<config:categories>
<value>600</value>
<value>605</value>
<value>610</value>
</config:categories>
<xsl:variable
name = "vCategories"
select = "document('')/*/config:categories/value"
/>
<xsl:key
name = "kPropertyByLabel"
match = "Properties/LabeledProperty/Value"
use = "../Label"
/>
<xsl:template match="/">
<xsl:choose>
<xsl:when test="key('kPropertyByLabel', 'Category Code') = $vCategories">
<!-- ... -->
</xsl:when>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
This works because the XPath = operator compares every node from the left hand side to every node on the right hand side when working on node sets (comparable to an SQL INNER JOIN).
Hence all you need to do is create a node set from your individual values. Using a temporary namespace you can do that right in your XSLT file.
Also note that I've introduced an <xsl:key> to make selecting property values by their label more efficient.
EDIT: You could also create an external config.xml file and do this:
<xsl:variable name="vConfig" select="document('config.xml')" />
<!-- ... -->
<xsl:when test="key('kPropertyByLabel', 'Category Code') = $vConfig/categories/value">
With XSLT 2.0 the concept of sequences has been added. It's simpler to do the same thing there:
<xsl:when test="key('kPropertyByLabel', 'Category Code') = tokenize('600,605,610', ',')">
This means you could easily pass in the string '600,605,610' as an external parameter.

XSLT Date Comparisons

<xsl:variable name="date1" select="2011-10-05"/>
<xsl:variable name="date2" select="2011-10-05"/>
<xsl:variable name="date3" select="2011-10-06"/>
<xsl:if test="$date2 = $date1 or $date2 < $date1">
..do something
</xsl:if>
<xsl:if test="$date3 = $date1 or $date3 > $date1">
.. do something
</xsl:if>
Both should evaluate true, but the second if doesn't. For the life of me I can't comprehended why!
In the actual transform the dates themselves are being drawn from an XML document but debugging through VS2010 i can see the values are as above.
Must be something fairly fundamental i'm doing wrong - any help would be brilliant!
I tried this in Oxygen/XML... select="2011-10-05 is being interpreted as an arithmetic expression, giving the value 1996 (2011 minus 10 minus 5) and "2011-10-06" is intrepreted as 1995.
What you want is
<xsl:variable name="date1" select="'2011-10-05'"/>
<xsl:variable name="date2" select="'2011-10-05'"/>
<xsl:variable name="date3" select="'2011-10-06'"/>
Note the extra single quotes.
From the XSLT 1.0 Specification:
If the variable-binding element has a select attribute, then the value
of the attribute must be an expression and the value of the variable
is the object that results from evaluating the expression.

XSLT line counter - is it that hard?

I have cheated every time I've needed to do a line count in XSLT by using JScript, but in this case I can't do that. I simply want to write out a line counter throughout an output file. This basic example has a simple solution:
<xsl:for-each select="Records/Record">
<xsl:value-of select="position()"/>
</xsl:for-each>
Output would be:
1
2
3
4
etc...
But what if the structure is more complex with nested foreach's :
<xsl:for-each select="Records/Record">
<xsl:value-of select="position()"/>
<xsl:for-each select="Records/Record">
<xsl:value-of select="position()"/>
</xsl:for-each>
</xsl:for-each>
Here, the inner foreach would just reset the counter (so you get 1, 1, 2, 3, 2, 1, 2, 3, 1, 2 etc). Does anyone know how I can output the position in the file (ie. a line count)?
While it is quite impossible to mark the line numbers for the serialization of an XML document (because this serialization per se is ambiguous), it is perfectly possible, and easy, to number the lines of regular text.
This transformation:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="text"/>
<xsl:template match="/">
<xsl:call-template name="numberLines"/>
</xsl:template>
<xsl:template name="numberLines">
<xsl:param name="pLastLineNum" select="0"/>
<xsl:param name="pText" select="."/>
<xsl:if test="string-length($pText)">
<xsl:value-of select="concat($pLastLineNum+1, ' ')"/>
<xsl:value-of select="substring-before($pText, '
')"/>
<xsl:text>
</xsl:text>
<xsl:call-template name="numberLines">
<xsl:with-param name="pLastLineNum"
select="$pLastLineNum+1"/>
<xsl:with-param name="pText"
select="substring-after($pText, '
')"/>
</xsl:call-template>
</xsl:if>
</xsl:template>
</xsl:stylesheet>
when applied on this XML document:
<t>The biggest airlines are imposing "peak travel surcharges"
this summer. In other words, they're going to raise fees
without admitting they're raising fees: Hey, it's not a $30
price hike. It's a surcharge! This comes on the heels of
checked-baggage fees, blanket fees, extra fees for window
and aisle seats, and "snack packs" priced at exorbitant
markups. Hotels in Las Vegas and elsewhere, meanwhile, are
imposing "resort fees" for the use of facilities (in other
words, raising room rates without admitting they're
raising room rates). The chiseling dishonesty of these
tactics rankles, and every one feels like another nail in
the coffin of travel as something liberating and
pleasurable.
</t>
produces the desired line-numbering:
1 The biggest airlines are imposing "peak travel surcharges"
2 this summer. In other words, they're going to raise fees
3 without admitting they're raising fees: Hey, it's not a $30
4 price hike. It's a surcharge! This comes on the heels of
5 checked-baggage fees, blanket fees, extra fees for window
6 and aisle seats, and "snack packs" priced at exorbitant
7 markups. Hotels in Las Vegas and elsewhere, meanwhile, are
8 imposing "resort fees" for the use of facilities (in other
9 words, raising room rates without admitting they're
10 raising room rates). The chiseling dishonesty of these
11 tactics rankles, and every one feels like another nail in
12 the coffin of travel as something liberating and
13 pleasurable.
A line in an XML file is not really the same as an element. In your first example you don't really count the lines - but the number of elements.
An XML file could look like this:
<cheeseCollection>
<cheese country="Cyprus">Gbejna</cheese><cheese>Liptauer</cheese><cheese>Anari</cheese>
</cheeseCollection>
Or the exact same XML file can look like this:
<cheeseCollection>
<cheese
country="Cyprus">Gbejna</cheese>
<cheese>Liptauer</cheese>
<cheese>Anari</cheese>
</cheeseCollection>
which the XSLT will interpet exactly the same - it will not really bother with the line breaks.
Therefore it's hard to show line numbers in the way you want using XSLT - it's not really meant for for that kind of parsing.
Someone correct me if I'm wrong, but I'd say you would need Javascript or some other scripting language to do what you want.
Thanks for the responses guys - yup you're totally correct, some external function is the only way to get this behaviour in XSLT. For those searching, this is how I did this when using a compiled transform in .Net 3.5:
Create a helper class for your function(s)
/// <summary>
/// Provides functional support to XSLT
/// </summary>
public class XslHelper
{
/// <summary>
/// Initialise the line counter value to 1
/// </summary>
Int32 counter = 1;
/// <summary>
/// Increment and return the line count
/// </summary>
/// <returns></returns>
public Int32 IncrementCount()
{
return counter++;
}
}
Add an instance to an args list for XSLT
XslCompiledTransform xslt = new XslCompiledTransform();
xslt.Load(XmlReader.Create(s));
XsltArgumentList xslArg = new XsltArgumentList();
XslHelper helper = new XslHelper();
xslArg.AddExtensionObject("urn:helper", helper);
xslt.Transform(xd.CreateReader(), xslArg, writer);
Use it in you XSLT
Put this in the stylesheet declaration element:
xmlns:helper="urn:helper"
Then use like so:
<xsl:value-of select="helper:IncrementCount()" />
Generally, position() is referring to the number of the current node relative to the entire batch of nodes that is being processed currently.
With your "nested for-each" example, consecutive numbering can easily be achieved when you stop nesting for-each constructs and just select all desired elements at once.
With this XML:
<a><b><c/><c/></b><b><c/></b></a>
a loop construct like this
<xsl:for-each "a/b">
<xsl:value-of select="position()" />
<xsl:for-each "c">
<xsl:value-of select="position()" />
</xsl:for-each>
</xsl:for-each>
will result in
11221
bccbc // referred-to nodes
but you could simply do this instead:
<xsl:for-each "a/b/c">
<xsl:value-of select="position()" />
</xsl:for-each>
and you would get
123
ccc // referred-to nodes