can we use dynamic variable name in the select statement in xslt? - xslt

Question

I wanted to use a dynamic variable name in the select statement in xslt.
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template match="/">
<xsl:variable name="input" select="input/message" />
<xsl:variable name="Name" select="'MyName'" />
<xsl:variable name="Address" select="MyAddress" />
<xsl:variable name="output" select="concat('$','$input')" /> <!-- This is not working -->
<output>
<xsl:value-of select="$output" />
</output>
</xsl:template>
The possible values for the variable "input" is 'Name' or 'Address'.
The select statement of the output variable should have a dynamic variable name based on the value of input variable. I don't want to use xsl:choose. I wanted to select the value dynamically.
Please provide me a solution.
Thanks,
dhinu

Answer 1

XSLT 1.0 and XSLT 2.0 don't have dynamic evaluation.
Solution for your problem:
This transformation:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:my="my:my">
<xsl:output method="text"/>
<my:values>
<name>MyName</name>
<address>MyAdress</address>
</my:values>
<xsl:template match="/">
<xsl:variable name="vSelector"
select="input/message"/>
<xsl:value-of select=
"document('')/*/my:values/*[name()=$vSelector]"/>
</xsl:template>
</xsl:stylesheet>
when applied on the following XML document:
<input>
<message>address</message>
</input>
produces the wanted, correct result:
MyAdress
when the same transformation is applied on this XML document:
<input>
<message>name</message>
</input>
again the wanted, correct result is produced:
MyName
Finally: If you do not wish to use the document() function, but would go for using the xxx:node-set() extension function, then this solution (looking very similar) is what you want, where you may consult your XSLTprocessor documentation for the exact namespace of the extension:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ext="http://exslt.org/common" >
<xsl:output method="text"/>
<xsl:variable name="vValues">
<name>MyName</name>
<address>MyAdress</address>
</xsl:variable>
<xsl:template match="/">
<xsl:variable name="vSelector"
select="input/message"/>
<xsl:value-of select=
"ext:node-set($vValues)/*[name()=$vSelector]"/>
</xsl:template>
</xsl:stylesheet>

Answer 2

Beside #Dimitre's good answer, for this particular case (output string value) you could also use:
<xsl:variable name="output"
select="concat(substring($Name, 1 div ($input = 'Name')),
substring($Address, 1 div ($input = 'Address')))"/>