Processing code from other xml-file

CHRD · March 2nd, 2010, 09:45 AM

Hello everybody,

I am looking for some hours for a solution. Should be very simple, but I can't find any hint. (Background: I am trying to build a DUL to HTML Transformation for diffxml. Maybe this is already done or anyone has a better idea to show xmldiffs...)

Problem: There is some pice of XSLT-code in one XML-file ('instructions.xml'), a source-file ('in.xml'), and the XSLT-Transformation ('test.xsl') working on the source-file. The Transformation should read instructions and use this as instructions for the transformation of in.xml. Instead I only can get the processor to read the instructions as text but not as instructions. (Maybe the code can better to be understood, than my English)

in.xml

Code:

<?xml version="1.0" encoding="iso-8859-1"?>
<root>
	<node name="blabla"/>
</root>

data.xml

Code:

<?xml version="1.0" encoding="iso-8859-1"?>
<root>
	<node name="blabla"/>
</root>

instructions.xml

Code:

<?xml version="1.0" encoding="iso-8859-1"?>
<root>
	<inst code="//node/@name"/>
</root>

test.xsl

Code:

<?xml version="1.0" encoding="iso-8859-1"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="text" encoding="iso-8859-1" />

<xsl:template match="/">
	<xsl:for-each select="collection('./?select=instructions.xml')/root/inst">
		<xsl:variable name="code"><xsl:value-of select="@code" /></xsl:variable>
			<xsl:value-of select="$code"/>
	</xsl:for-each>
	
	<xsl:value-of select="//node/@name" />
</xsl:template>

</xsl:stylesheet>

Any hints are really apreciated!

Best regards

Christian

Martin Honnen · March 2nd, 2010, 09:51 AM

If you use Saxon 9 then you might want to look into using an extension function like http://www.saxonica.com/documentatio.../evaluate.html

CHRD · March 2nd, 2010, 11:46 AM

Thank You for that answer.

Did I get that right?

1. There is no way in XSLT to build dynamic code.
2. I have to pay to use this function in saxon (saxon pe).

What is about merging the two files to one "executable" and use this?

Regards Christian

Martin Honnen · March 2nd, 2010, 11:57 AM

Pure XSLT does not have any "eval" functionality to eval a string representing an XPath expression or even an XSLT stylesheet or template.

I pointed you to the Saxon 9.1 documentation of that extension function. It is available in the open source basic Saxon 9.1 version.
If you want to use Saxon 9.2 then you are right, the extension function is not available in the open source version, you need a license for one of the commercial versions.

As for building an "excutable", an XSLT stylesheet is XML thus it can be the input and/or the output of an XSLT transformation. That way you would not need an extension function but you need to apply two steps of transformation, one that generates a stylesheet and a second one that applies it.

mhkay · March 2nd, 2010, 12:02 PM

Writing code to construct a new stylesheet and then compiling that stylesheet is certainly an alternative, if time is more plentiful than money.

CHRD · March 2nd, 2010, 02:56 PM

Thank you very much for the answers. Time is always rare in programming: There are too many other things on the world to do... But: I have to write code that will run in a very 'unfriendly' environment. This is not up to me.

If anyone is interested in a working example, let me know. I could post it here (some 10 kB).

What would have saved me writing a lot of lines: A hint to xsl:namespace-alias. Well: I am still learning. Thank You anyway!

Best regards

Christian