XSLT: variables and "empty" labels - variables

I have an XML datafile containing among other things a string of arbitrarily many comma separated values. I want those values to be displayed in a web browser as a list with one value per line. So I wrote an XSLT template that takes this string, displays the first value followed by a linebreak tag (<br/>), properly name-spaced, and resources with the remainder of the string. In effect, the commas are being replaced by HTML <br/> tags.
Now, when I store the result of calling that template in a xsl:variable, and display that through xsl:value-of, then the HTML tags disappear: what is shown is the string minus the commas.
When I display the result directly by having the xsl:call-template in place of the xsl:value-of, all is fine, and the values appear in a list.
So, what's going on?
Is this behavior an implementation artifact, or is it standard XSLT?

Use xsl:copy-of instead of xsl:value-of if you want to output nodes (like your br elements), xsl:value-of creates a simple text node with the string value(s) selected.
Here is an example that shows the difference between xsl:value-of and xsl:copy-of, you will note that it is not the use of the variable with newly created br elements that makes the difference, it is simply the use of xsl:value-of that creates a text() node with the string conversion of the selection:
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0">
<xsl:output method="html" indent="yes" version="5" doctype-system="about:legacy-doctype"/>
<xsl:variable name="var">Phrase 1.<br/>Phrase 2.<br/>Phrase 3.</xsl:variable>
<xsl:template match="/">
<html>
<head>
<title>.NET XSLT Fiddle Example</title>
</head>
<body>
<section>
<h1>Example 1: value-of</h1>
<xsl:value-of select="$var"/>
</section>
<section>
<h1>Example 2: copy-of</h1>
<xsl:copy-of select="$var"/>
</section>
<xsl:apply-templates select="//p"/>
<xsl:apply-templates select="//p" mode="copy-of"/>
</body>
</html>
</xsl:template>
<xsl:template match="p">
<section>
<h1>Example 1: value-of</h1>
<xsl:value-of select="."/>
</section>
</xsl:template>
<xsl:template match="p" mode="copy-of">
<section>
<h1>Example 1: copy-of</h1>
<xsl:copy-of select="."/>
</section>
</xsl:template>
</xsl:stylesheet>
https://xsltfiddle.liberty-development.net/gWmuiJy/1
Output is
Example 1: value-of
Phrase 1.Phrase 2.Phrase 3.
Example 2: copy-of
Phrase 1.
Phrase 2.
Phrase 3.
Example 1: value-of
Line 1.Line 2.Line 3.
Example 1: copy-of
Line 1.
Line 2.
Line 3.

It seems that you hit the boundaries of the RTF ("Result tree fragment"):
When you use an XML fragment to initialize a variable or a parameter, then the variable or parameter is of the
"result tree fragment" datatype. This is an XSLT 1.0 specific datatype [just like node-set, but slightly different].
A result tree fragment is equivalent to a node-set that contains just the root node.
You cannot apply operators like "/", "//" or predicate on a result tree fragments. They are only applicable for node-set datatypes.
[...]
a) In XSLT 1.0
The resolution of this is to convert the result tree fragment into a node-set. I am not aware of any oracle specific xpath extension functions that can do this trick for you.
You could use EXSLT to achieve this.
b) Use XSLT 2.0
You can code your transformations in XSLT 2.0. XSLT 2.0 deprecates ResultTreeFragments i.e. if you are modeling an XSLT 2.0 transformation, and you create a variable or a parameter that holds a tree fragment, it is implicitly a node sequence.
So without using an XSLT version greater than 1, you're out of luck. So better use XSLT-2.0 or 3.0 to solve this problem.
Is this behavior an implementation artifact, or is it standard XSLT?
It is standard for XSLT-1.0, but not for XSLT-2.0+.

Related

XSLT 1 - How can I replace '&' with '&' in XML file?

I need to find solution to fix by using XSLT 1! Most of sent XML files well formatted and someone make mess by adding characters (& < >. . .). Any way to do replace this on my side? I tried XSLT 2 and Replace function does not work as I use XSLT processor from Microsoft
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:saxon="http://saxon.sf.net/"
exclude-result-prefixes="xs saxon"
version="2.0">
<xsl:param name="path" select="'file:///E:/foo.xml'"></xsl:param>
<xsl:template match="/">
<xsl:copy-of select="unparsed-text($path)"></xsl:copy-of>
<xsl:copy-of select="saxon:parse(replace(unparsed-text($path), '&', '&amp;'))"/>
</xsl:template>
</xsl:stylesheet>
Any other suggestion how to solve this issue. for example I have input XML file like:
<?xml version="1.0" encoding="UTF-8"?>
<name>Stack & Exchange</name>
And is fail on '&' character.
Please advice!
Thank you
Conclusion
Two observations
XSLT requires at least a well formed XML document at the input, so I can't use it to correct invalid XML
(it is an XML transformation language)
in order to use replace or escape invalid characters of XML on input I need to make sure that I use an XSLT 2.0 processor
(I use Microsoft processor XSLT 1.0)
I see two options
If I receive an error on input, investigate and validate manually and send back the error message. - THIS IS I TRIED TO AVOID! (Use text tools like notepad++, excel to find an issue).
write a correcting parser in the .net language to fix before loading as XML

Can we declare global variable and add/Remove/Check value from it?

I want to achieve
Declare global variable having no value
<xsl:variable name="IsEqual"/>
Check variable value and change according to condition
<xsl:choose>
**// Checking value equal or not**
<xsl:when test="name=$name">
<xsl:choose>
**//Checking variable value**
<xsl:when test="$IsEqual !='Unequal'">
**//Setting variable value**
<xsl:variable name="IsEqual" Select="Equal"/>
</xsl:when>
</xsl:choose>
</xsl:when>
<xsl:otherwise>
**//Setting variable value**
<xsl:variable name="IsEqual" Select="Unequal"/>
</xsl:otherwise>
</xsl:choose>
<xsl:value-of select="$IsEqual"/>
Expected output value of variable $IsEqual.. IF it is not possible then what is another way to achieve this? What should I use instead of variable?
"It's not a bug, it's a feature": XSLT variables are designed not to be changeable. Actually they could be named constants. Working around that is difficult, it can be done using parameters. In most cases that isn't necessary if you use the XSLT programming attempt, where the programm is driven by the data through templates.
The answer to your question is no.
Copied this (own) text from XML and Variables
#Sam: What do you want to accomplish using a global variable? Where do you want to check for equality? I have no idea what you want to do so I can only give you a general example.
Try this xml file:
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="test.xsl"?>
<root>
<data check="value1">This is data 1</data>
<data check="value2">This is data 2</data>
<data check="value3">This is data 3</data>
</root>
with this xslt file:
<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:variable name="v">value2</xsl:variable>
<xsl:template match="/">
<xsl:apply-templates select="root/data[#check = $v]"/>
</xsl:template>
<xsl:template match="data">
<xsl:value-of select="."/>
</xsl:template>
</xsl:stylesheet>
Only the second data element will show up as this one matches the global variable, which stays the same all the time. If you want different values to match with, you can put them into your data file instead using a variable and compare the different elements.
For testing just save the two files (test.xml and test.xsl) into one directory and open test.xml with your browser.
#Sam again: As you insist on changing an xslt variable I have to repeat that this can't be done. Maybe there is a way around using the environment xslt is running in. E.g. PHP, where you can pass functions into the script. I described the technique here: Can PHP communicate with XSLT?
The xslt spec says:
XSLT does not provide an equivalent to the Java assignment operator
x = "value";
because this would make it harder to create an implementation that processes a document other than in a batch-like way, starting at the beginning and continuing through to the end.
(See http://www.w3.org/TR/xslt#variables to prove my answer "no" to your question is correct :-)

Looping a variable length array with namespaces in XSLT

My previous question[1] is related to this. I found the answer for that. Now I want to loop a variable length array with namespaces. My array:
<ns:array xmlns:ns="http://www.example.org">
<value>755</value>
<value>5861</value>
<value>4328</value>
<value>2157</value>
<value>1666</value>
</ns:array>
My XSLT code:(have added the namespace in the root)
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ns1="http://www.example.org">
<xsl:template match="/">
<xsl:variable name="number" select="ns:array" />
<xsl:for-each select="$number">
<xsl:value-of select="$number" />
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
[1]https://stackoverflow.com/questions/20287219/looping-a-variable-length-array-in-xslt
IMHO you confused yourself by introducing a variable called number which actually contains a node set of value tags. Then, as a consequence you used your variable as singe item/node which does not yield the desired result (presumingly, since you did not really tell us what you want to do with the values).
Also, I think your question does not really have anything to with namespace issues as such. You just have to make sure that the namespaces in your select expressions match the namespaces in your input file.
I would suggest to do without the variable and change the way you retrieve the current value:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ns1="http://www.example.org">
<xsl:template match="/">
<xsl:for-each select="ns:array">
<!-- Inside here you can work with the `value` tag as the _current node_.
There are two most likely ways to do this. -->
<!-- a) Copy the whole tag to the output: -->
<xsl:copy-of select="." />
<!-- or b1) Copy the text part contained in the tag to the output: -->
<xsl:value-of select="." />
<!-- If you want to be on the safe side with respect to white space
you can also use this b2). This would handle the case that your output
is required not to have any white space in it but your imput XML has
some. -->
<xsl:value-of select="normalize-space(.)" />
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>

using regular expression in xslt 1.0

I want to use regular expression in xslt 1.0
Input
<book>
<p>
The clavicle is broken more <inlinegraphic></inlinegraphic>
mad_2235.eps often than any other bone in the body
</p>
</book>
Output
<book>
<p>
The clavicle is broken more
<graphic name="mad_2235.eps" source="ISBN" in-line="yes"/>
often than any other bone in the body
</p>
</book>
Thanks,
Muthu
XSLT 1.0 doesn't do regular expressions, but I don't think you need them in this case. I would start with an identity transformation
<!-- copy everything from input to output verbatim, except where overridden
by more specific templates -->
<xsl:template match="#*|node()">
<xsl:copy><xsl:apply-templates select="#*|node()" /></xsl:copy>
</xsl:template>
then override this with a template that matches any text node that immediately follows an inlinegraphic element and contains .eps
<xsl:template match="text()[preceding-sibling::node()[1][self::inlinegraphic]]
[contains(., '.eps')]">
<!-- take everything before the first .eps as the graphic name -->
<graphic name="{normalize-space(substring-before(., '.eps'))}.eps"
source="ISBN" in-line="yes"/>
<!-- and leave everything after that as normal text -->
<xsl:value-of select="substring-after(., '.eps')" />
</xsl:template>
And finally add a template to remove the inlinegraphic element itself
<xsl:template match="inlinegraphic" />

Can disable-output-escaping be set using a template parameter?

Why won't the following work in XSLT1.0?
<xsl:template name="GenerateSummaryOld">
<xsl:param name="Content" />
<xsl:param name="Length" />
<xsl:param name="DisableOutputEscaping" />
<xsl:value-of select="substring($Content, 1, $Length)" disable-output-escaping="$DisableOutputEscaping" />
<xsl:if test="string-length($Content) > $Length"><i>...text has been shortened</i></xsl:if>
</xsl:template>
I'm using the following when calling the template:
<xsl:with-param name="DisableOutputEscaping">no</xsl:with-param>
I'm trying this in a SharePoint Content Query WebPart but I get a web part error. If I hard-code disable-output-escaping as "yes" or "no" in the template, i get no error.
Short answer: the value of disable-output-escaping must be specified literally in the XSLT stylesheet; it cannot be calculated at stylesheet execution time.
That is, the behavior you are observing is the behavior prescribed by the language definition.
Longer answer: The XSLT 1.0 spec shows the syntax of xsl:value-of like this (more or less):
<!-- Category: instruction -->
<xsl:value-of
select = string-expression
disable-output-escaping = "yes" | "no" />
Note that "string-expression" is italicized here; it means that the select attribute has as its value not the string "string-expression" but any XPath expression which can be evaluated and coerced to a string. But the "yes" and "no" of disable-output-escaping are not italicized, not described as being an expression, and not described as being an attribute-value template. The "yes" or "no" value must be given literally.
The closest the spec comes to saying this explicitly (that I could find) is the note in section 7.6.2 on attribute value templates:
NOTE:Not all attributes are interpreted as attribute value templates. Attributes whose value is an expression or pattern, attributes of top-level elements and attributes that refer to named XSLT objects are not interpreted as attribute value templates. ...
This is one of a number of early-binding constraints in XSLT designed to ensure that stylesheets could be compiled and not just interpreted.
The explanation was provided in the good answer by C. M. Sperberg-McQueen.
Here is a workaround:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:variable name="vAmp">&</xsl:variable>
<xsl:variable name="vYesNo" select="'yes'"/>
<xsl:template match="/">
<xsl:choose>
<xsl:when test="$vYesNo = 'yes'">
<xsl:value-of select="$vAmp" disable-output-escaping="yes"/>
</xsl:when>
<xsl:when test="$vYesNo = 'no'">
<xsl:value-of select="$vAmp" disable-output-escaping="no"/>
</xsl:when>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied on any XML document (not used), the result is:
&
If we replace:
<xsl:variable name="vYesNo" select="'yes'"/>
with:
<xsl:variable name="vYesNo" select="'no'"/>
the result of the modified transformation now is:
&