Using max in a variable in XSLT 1.0 - xslt

Question

can I use max function in a variable in XSLT 1?
I need to find a maximum value inside some nodes and I'll need to call this from more places.
So I tried to create a template:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt"
xmlns:essox="urn:essox-scripts">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template name="Field001_max_dluznych_splatek">
<xsl:param name="CrRep"/>
<xsl:variable name="PocetDluznychSplatekSplatky">
<xsl:value-of
select="max($CrRep
/Response
/ContractData
/Installments
/InstDetail
/NrOfDueInstalments)" />
</xsl:variable>
<xsl:variable name="PocetDluznychSplatekKarty">
<xsl:value-of
select="max($CrRep
/Response
/ContractData
/Cards
/CardDetail
/NrOfDueInstalments)" />
</xsl:variable>
<xsl:choose>
<xsl:when test="$PocetDluznychSplatekSplatky
>= $PocetDluznychSplatekKarty">
<xsl:value-of select="$PocetDluznychSplatekSplatky"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$PocetDluznychSplatekKarty"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
In XML Spy I get this error:
Error in XPath expression Unknown
function - Name and number of
arguments do not match any function
signature in the static context -
'max'.
What is wrong?
Thanks a lot,
Peter

Answer 1

Use the well known maximum idiom:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt"
xmlns:essox="urn:essox-scripts">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template name="Field001_max_dluznych_splatek">
<xsl:param name="CrRep"/>
<xsl:variable name="PocetDluznychSplatekSplatky">
<xsl:call-template name="maximun">
<xsl:with-param name="pSequence"
select="$CrRep
/Response
/ContractData
/Installments
/InstDetail
/NrOfDueInstalments"/>
</xsl:call-template>
</xsl:variable>
<xsl:variable name="PocetDluznychSplatekSplatky">
<xsl:call-template name="maximun">
<xsl:with-param name="pSequence"
select="$CrRep
/Response
/ContractData
/Cards
/CardDetail
/NrOfDueInstalments"/>
</xsl:call-template>
</xsl:variable>
<xsl:choose>
<xsl:when test="$PocetDluznychSplatekSplatky
>= $PocetDluznychSplatekKarty">
<xsl:value-of select="$PocetDluznychSplatekSplatky"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$PocetDluznychSplatekKarty"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
<xsl:template name="maximun">
<xsl:param name="pSequence"/>
<xsl:for-each select="$pSequence">
<xsl:sort select="." data-type="number" order="descending"/>
<xsl:if test="position()=1">
<xsl:value-of select="."/>
</xsl:if>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
Note: In a named template for reuse.

Answer 2

There is no max function in XSLT 1.0. You can work around this by sorting your elements in descending order and then taking the value of the first one.
Here's another (slower) way to do it:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:variable name="PocetDluznychSplatekSplatky"
select="/test/PocetDluznychSplatekSplatky/val[not(../val > .)][1]" />
<xsl:variable name="PocetDluznychSplatekKarty"
select="/test/PocetDluznychSplatekKarty/val[not(../val > .)][1]" />
<xsl:template match="/">
<xsl:choose>
<xsl:when
test="$PocetDluznychSplatekSplatky >=
$PocetDluznychSplatekKarty">
<xsl:value-of select="$PocetDluznychSplatekSplatky" />
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$PocetDluznychSplatekKarty" />
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
Sample source document:
<test>
<PocetDluznychSplatekSplatky>
<val>22</val>
<val>3241</val>
<val>13</val>
</PocetDluznychSplatekSplatky>
<PocetDluznychSplatekKarty>
<val>1</val>
<val>3234341</val>
<val>13</val>
</PocetDluznychSplatekKarty>
</test>
Output:
3234341
The XPath in each variable's select looks like this:
/test/PocetDluznychSplatekSplatky/val[not(../val > .)][1]
Or, select the val element having no val siblings with a greater value (i.e. the max).
(Obviously, you'll need to adjust the XPath to fit your source document.)
Note: The sort solution performs much better (assuming an n*log(n) sort implementation). The second approach needs to compare each val to every one of its siblings and is therefore quadratic.