Subject: Re: Emulating XPATH2 range in XSLT 1.0
From: Dimitre Novatchev <dnovatchev@xxxxxxxxx>
Date: Wed, 29 Jul 2009 06:24:49 -0700
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You are discovering the "iter" function/template of FXSL 1.x, which
has been available for 7+ years :) :
Here is the file generateFromTo.xsl from Fxsl 1.x :
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ext="http://exslt.org/common"
xmlns:f="http://fxsl.sf.net/"
xmlns:myIncrement="f:myIncrement"
exclude-result-prefixes="ext f myIncrement"
>
<xsl:import href="iter.xsl"/>
<!-- To be applied on any xml file -->
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:template match="/">
<xsl:call-template name="generateBatch">
<xsl:with-param name="pFrom" select="3"/>
<xsl:with-param name="pTo" select="300"/>
</xsl:call-template>
</xsl:template>
<myIncrement:myIncrement/>
<xsl:template name="generateBatch">
<xsl:param name="pFrom"/>
<xsl:param name="pTo"/>
<xsl:variable name="vFunIncr"
select="document('')/*/myIncrement:*[1]"/>
<xsl:variable name="vResult">
<xsl:call-template name="scanIter">
<xsl:with-param name="arg1" select="$pTo - $pFrom + 1"/>
<xsl:with-param name="arg2" select="$vFunIncr"/>
<xsl:with-param name="arg3" select="$pFrom - 1"/>
<xsl:with-param name="arg4" select="'obj'"/>
</xsl:call-template>
</xsl:variable>
<xsl:copy-of select="ext:node-set($vResult)/*[position() > 1]"/>
</xsl:template>
<xsl:template match="myIncrement:*" mode="f:FXSL">
<xsl:param name="arg1"/>
<childnode>
<xsl:value-of select="$arg1 + 1"/>
</childnode>
</xsl:template>
</xsl:stylesheet>
When applied on any XML file (ignored), it produces the wanted (long
to be included) result.
The above was written at the time with demonstration purposes and uses
simple recursion.
I will provide a DVC-style of the same transformation, which has no
problems with recursion stack overflow for big and practical values of
$pTo - $pFrom.
--
Cheers,
Dimitre Novatchev
---------------------------------------
Truly great madness cannot be achieved without significant intelligence.
---------------------------------------
To invent, you need a good imagination and a pile of junk
-------------------------------------
Never fight an inanimate object
-------------------------------------
You've achieved success in your field when you don't know whether what
you're doing is work or play
On Wed, Jul 29, 2009 at 3:37 AM, Hermann
Stamm-Wilbrandt<STAMMW@xxxxxxxxxx> wrote:
>
> Emulating the XSLT2 statement
> B B for $f in 1 to 10000
> B B B ...
>
> may be done in XSLT1 (providing similar scoping of variable $f) by:
> B B <xsl:for-each select="range:to(1,10000)">
> B B B <xsl:variable name="f" select="."/>
> B B B ...
> B B </xsl:for-each>
>
> In this case the complete set of numbers is generated into memory.:
> For bigger iteration count ("1 to 1000000" in T2.xsl) this
> may cause problems for the XSLT processor.
>
> Therefore "loop.xsl" may be used (T2.xsl, T3.xsl) to just iterate and
> do not generate all the numbers into memory. In order to allow for
> different bodies of the loops a template with name "loop" is called.
> Different implementations (body2.xsl, body3.xsl) are included
> together with "loop.xsl" into different stylesheets (T2.xsl, T3.xsl).
>
>
> I teststed this successfully with the following XSLT 1.0 processors:.
> - xsltproc (Using libxml 20626, libxslt 10117 and libexslt 813)
> - xalan-j (2.7.1)
> - IBM Websphere DataPower compiler
>
>
> All files may be downloaded here:
> http://www.stamm-wilbrandt.de/en/xsl-list/range/files.zip
>
> Find an example execution for T3.xsl at the bottom.
>
> $ cat range.xsl
> <xsl:stylesheet version="1.0"
> B xmlns:xsl B = "http://www.w3.org/1999/XSL/Transform"
> B xmlns:exslt = "http://exslt.org/common"
> B xmlns:func B = "http://exslt.org/functions"
> B xmlns:range = "urn:xpath1range"
> B extension-element-prefixes="func">
>
> B <func:function name="range:to">
> B B <xsl:param name="a"/>
> B B <xsl:param name="b"/>
>
> B B <func:result select="exslt:node-set(range:TO($a,$b))/*/text()"/>.
> B </func:function>
>
> B <func:function name="range:TO">
> B B <xsl:param name="a"/>
> B B <xsl:param name="b"/>
>
> B B <xsl:choose>
> B B B <xsl:when test="$a > $b"/>>
> B B B <xsl:when test="$a = $b">>>
> B B B B <func:result>
> B B B B B <e><xsl:value-of select="$a"/></e>
> B B B B </func:result>
> B B B </xsl:when>
> B B B <xsl:otherwise>>
> B B B B <xsl:variable name="m" select="$a + floor(($b - $a) div 2)"/>
> B B B B <func:result>
> B B B B B <xsl:copy-of select="range:TO($a,$m)"/>
> B B B B B <xsl:copy-of select="range:TO($m+1,$b)"/>
> B B B B </func:result>
> B B B </xsl:otherwise>
> B B </xsl:choose>
> B </func:function>
>
> </xsl:stylesheet>>
>
> $ cat loop.xsl
> <xsl:stylesheet version="1.0"
> B xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
>
> B <xsl:template name="loop">
> B B <xsl:param name="from"/>
> B B <xsl:param name="to"/>
>
> B B <xsl:choose>
> B B B <xsl:when test="$from > $to"/>
> B B B <xsl:when test="$from = $to">
> B B B B <xsl:call-template name="body">
> B B B B B <xsl:with-param name="iter" select="$from"/>
> B B B B </xsl:call-template>
> B B B </xsl:when>
> B B B <xsl:otherwise>
> B B B B <xsl:variable name="middle"
> B B B B B B B B B B B select="$from + floor(($to - $from) div
2)"/>
>
> B B B B <xsl:call-template name="loop">
> B B B B B <xsl:with-param name="from" select="$from" />
> B B B B B <xsl:with-param name="to" select="$middle" />
> B B B B </xsl:call-template>
> B B B B <xsl:call-template name="loop">
> B B B B B <xsl:with-param name="from" select="$middle+1" />
> B B B B B <xsl:with-param name="to" select="$to" />
> B B B B </xsl:call-template>
> B B B </xsl:otherwise>
> B B </xsl:choose>
> B </xsl:template>
>
> </xsl:stylesheet>
>
> $ cat T1.xsl
> <xsl:stylesheet version="1.0"
> B xmlns:xsl B = "http://www.w3.org/1999/XSL/Transform"
> B xmlns:range = "urn:xpath1range">
>
> B <xsl:include href="range.xsl"/>>
>
> B <xsl:template match="/">.
> B <!--:
> B B for $f in 1 to 10000
> B B B ...
>
> B B emulated by:
> B B <xsl:for-each select="range:to(1,10000)">
> B B B <xsl:variable name="f" select="."/>
> B B B ...
> B B </xsl:for-each>
> B -->
> B B <xsl:for-each select="range:to(1,10000)">
> B B B <xsl:variable name="f" select="."/>
>
> B B B <xsl:value-of select="$f"/>
> B B </xsl:for-each>
> B </xsl:template>
>
> </xsl:stylesheet>
>
> $ cat T2.xsl
> <xsl:stylesheet version="1.0"
> B xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
>
> B <xsl:output method="text"/>
>
> B <xsl:include href="loop.xsl"/>
> B <xsl:include href="body2.xsl"/>
>
> B <xsl:template match="/">.
> B B <xsl:call-template name="loop">
> B B B <xsl:with-param name="from" select="1" />
> B B B <xsl:with-param name="to" select="1000000" />
> B B </xsl:call-template>
> B </xsl:template>
>
> </xsl:stylesheet>
> $ cat body2.xsl
> <xsl:stylesheet version="1.0"
> B xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
>
> B <xsl:template name="body">
> B B <xsl:param name="iter"/>
> B B <xsl:value-of select="$iter"/>
> B </xsl:template>
> </xsl:stylesheet>
>
> $ cat T3.xsl
> <xsl:stylesheet version="1.0"
> B xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
> B <xsl:output method="xml" />
>
> B <xsl:include href="loop.xsl"/>
> B <xsl:include href="body3.xsl"/>
>
> B <xsl:template match="/">.
> B B <file>
> B B B <xsl:call-template name="loop">
> B B B B <xsl:with-param name="from" select="data/loop/@from" />)
> B B B B <xsl:with-param name="to" select="data/loop/@to" />
> B B B </xsl:call-template>
> B B </file>
> B </xsl:template>
>
> </xsl:stylesheet>
> $ cat body3.xsl
> <xsl:stylesheet version="1.0"
> B xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
>
> B <xsl:template name="body">
> B B <xsl:param name="iter"/>
> B B <data>
> B B B <no><xsl:value-of select="$iter"/></no>
> B B B <sqr><xsl:value-of select="$iter*$iter"/></sqr>
> B B B <name><xsl:value-of select="data/pers/lname" />, <xsl:value-of
> select="data/pers/fname" /></name>
> B B </data>>
> B </xsl:template>
> </xsl:stylesheet>
> $ cat data.xml
> <data>
> B <loop from="3" to="5"/>
> B <pers>
> B B <lname>Smith</lname>>
> B B <fname>John</fname>>>
> B </pers>
> </data>
>
> $ xsltproc T3.xsl data.xml | tidy -q -xml
> <?xml version="1.0"?>
> <file>
> B <data>
> B B <no>3</no>
> B B <sqr>9</sqr>.
> B B <name>Smith, John</name>
> B </data>>
> B <data>>>
> B B <no>4</no>
> B B <sqr>16</sqr>
> B B <name>Smith, John</name>
> B </data>>
> B <data>>>
> B B <no>5</no>
> B B <sqr>25</sqr>
> B B <name>Smith, John</name>
> B </data>>
> </file>
>
> $
>
>
> Mit besten GrC<Cen / Best wishes,
>
> Hermann Stamm-Wilbrandt
> Developer, XML Compiler
> WebSphere DataPower SOA Appliances
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