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Re: Emulating XPATH2 range in XSLT 1.0

Subject: Re: Emulating XPATH2 range in XSLT 1.0
From: Hermann Stamm-Wilbrandt <STAMMW@xxxxxxxxxx>
Date: Wed, 29 Jul 2009 15:51:08 +0200
Re:  Emulating XPATH2 range in XSLT 1.0
> You are discovering the "iter" function/template of FXSL 1.x, which
> has been available for 7+ years :)  :

So "iter" corresponds to template named "loop".


"rannge:to" from below post does need very little overhead in
writing over the XSLT2 statement "for $f in 1 to 10000 ...".
For small iteration count (<10000) I would prefer it over "loop".

Does FXSL provide an equivalent to "range:to" ?


Mit besten Gr|_en / Best wishes,

Hermann Stamm-Wilbrandt
Developer, XML Compiler
WebSphere DataPower SOA Appliances



             Dimitre Novatchev
             <dnovatchev@gmail
             .com>                                                      To
                                       xsl-list@xxxxxxxxxxxxxxxxxxxxxx
             07/29/2009 03:24                                           cc
             PM
                                                                   Subject
                                       Re:  Emulating XPATH2 range in
             Please respond to         XSLT 1.0
             xsl-list@xxxxxxxx
              lberrytech.com








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
>    for $f in 1 to 10000
>      ...
>
> may be done in XSLT1 (providing similar scoping of variable $f) by:
>    <xsl:for-each select="range:to(1,10000)">
>      <xsl:variable name="f" select="."/>
>      ...
>    </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"
>  xmlns:xsl   = "http://www.w3.org/1999/XSL/Transform"
>  xmlns:exslt = "http://exslt.org/common"
>  xmlns:func  = "http://exslt.org/functions"
>  xmlns:range = "urn:xpath1range"
>  extension-element-prefixes="func">
>
>  <func:function name="range:to">
>    <xsl:param name="a"/>
>    <xsl:param name="b"/>
>
>    <func:result select="exslt:node-set(range:TO($a,$b))/*/text()"/>.
>  </func:function>
>
>  <func:function name="range:TO">
>    <xsl:param name="a"/>
>    <xsl:param name="b"/>
>
>    <xsl:choose>
>      <xsl:when test="$a > $b"/>>
>      <xsl:when test="$a = $b">>>
>        <func:result>
>          <e><xsl:value-of select="$a"/></e>
>        </func:result>
>      </xsl:when>
>      <xsl:otherwise>>
>        <xsl:variable name="m" select="$a + floor(($b - $a) div 2)"/>
>        <func:result>
>          <xsl:copy-of select="range:TO($a,$m)"/>
>          <xsl:copy-of select="range:TO($m+1,$b)"/>
>        </func:result>
>      </xsl:otherwise>
>    </xsl:choose>
>  </func:function>
>
> </xsl:stylesheet>>
>
> $ cat loop.xsl
> <xsl:stylesheet version="1.0"
>  xmlns:xsl=">http://www.w3.org/1999/XSL/Transform">
>
>  <xsl:template name="loop">
>    <xsl:param name="from"/>
>    <xsl:param name="to"/>
>
>    <xsl:choose>
>      <xsl:when test="$from &gt; $to"/>
>      <xsl:when test="$from = $to">
>        <xsl:call-template name="body">
>          <xsl:with-param name="iter" select="$from"/>
>        </xsl:call-template>
>      </xsl:when>
>      <xsl:otherwise>
>        <xsl:variable name="middle"
>                      select="$from + floor(($to - $from) div 2)"/>
>
>        <xsl:call-template name="loop">
>          <xsl:with-param name="from" select="$from" />
>          <xsl:with-param name="to" select="$middle" />
>        </xsl:call-template>
>        <xsl:call-template name="loop">
>          <xsl:with-param name="from" select="$middle+1" />
>          <xsl:with-param name="to" select="$to" />
>        </xsl:call-template>
>      </xsl:otherwise>
>    </xsl:choose>
>  </xsl:template>
>
> </xsl:stylesheet>
>
> $ cat T1.xsl
> <xsl:stylesheet version="1.0"
>  xmlns:xsl   = "http://www.w3.org/1999/XSL/Transform"
>  xmlns:range = "urn:xpath1range">
>
>  <xsl:include href="range.xsl"/>>
>
>  <xsl:template match="/">.
>  <!--:
>    for $f in 1 to 10000
>      ...
>
>    emulated by:
>
<xsl:for-each select="range:to(1,10000)">
>      <xsl:variable name="f"
select="."/>
>      ...
>    </xsl:for-each>
>  -->
>    <xsl:for-each select="range:to(1,10000)">
>      <xsl:variable name="f" select="."/>
>
>      <xsl:value-of select="$f"/>
>    </xsl:for-each>
>  </xsl:template>
>
> </xsl:stylesheet>
>
> $ cat T2.xsl
> <xsl:stylesheet version="1.0"
>  xmlns:xsl="http://www.w3.org/1999/XSL/Transform>">
>
>  <xsl:output method="text"/>
>
>  <xsl:include href="loop.xsl"/>
>  <xsl:include href="body2.xsl"/>
>
>  <xsl:template match="/">.
>    <xsl:call-template name="loop">
>      <xsl:with-param name="from" select="1" />
>      <xsl:with-param name="to" select="1000000" />
>    </xsl:call-template>
>  </xsl:template>
>
> </xsl:stylesheet>
> $ cat body2.xsl
> <xsl:stylesheet version="1.0"
>  xmlns:xsl="http://www.w3.org/1999/XSL/Transform>">
>
>  <xsl:template name="body">
>    <xsl:param name="iter"/>
>    <xsl:value-of select="$iter"/>
>  </xsl:template>
> </xsl:stylesheet>
>
> $ cat T3.xsl
> <xsl:stylesheet version="1.0"
>  xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
>  <xsl:output method="xml" />
>
>  <xsl:include href="loop.xsl"/>
>  <xsl:include href="body3.xsl"/>
>
>  <xsl:template match="/">.
>    <file>
>      <xsl:call-template name="loop">
>        <xsl:with-param name="from" select="data/loop/@from" />)
>        <xsl:with-param name="to" select="data/loop/@to" />
>      </xsl:call-template>
>    </file>
>  </xsl:template>
>
> </xsl:stylesheet>
> $ cat body3.xsl
> <xsl:stylesheet version="1.0"
>  xmlns:xsl="http://www.w3.org/1999/XSL/Transform>">
>
>  <xsl:template name="body">
>    <xsl:param name="iter"/>
>    <data>
>      <no><xsl:value-of select="$iter"/></no>
>      <sqr><xsl:value-of select="$iter*$iter"/></sqr>
>      <name><xsl:value-of select="data/pers/lname" />, <xsl:value-of
> select="data/pers/fname" /></name>
>    </data>>
>  </xsl:template>
> </xsl:stylesheet>
> $ cat data.xml
> <data>
>  <loop from="3" to="5"/>
>  <pers>
>    <lname>Smith</lname>>
>    <fname>John</fname>>>
>  </pers>
> </data>
>
> $ xsltproc T3.xsl data.xml | tidy -q -xml
> <?xml version="1.0"?>
> <file>
>  <data>
>    <no>3</no>
>    <sqr>9</sqr>.
>    <name>Smith, John</name>
>  </data>>
>  <data>>>
>    <no>4</no>
>    <sqr>16</sqr>
>    <name>Smith, John</name>
>  </data>>
>  <data>>>
>    <no>5</no>
>    <sqr>25</sqr>
>    <name>Smith, John</name>
>  </data>>
> </file>
>
> $
>
>
> Mit besten Gr|_en / Best wishes,
>
> Hermann Stamm-Wilbrandt
> Developer, XML Compiler
> WebSphere DataPower SOA Appliances
> ----------------------------------------------------------------------
> IBM Deutschland Research & Development GmbH
> Vorsitzender des Aufsichtsrats: Martin Jetter
> Geschdftsf|hrung: Erich Baier
> Sitz der Gesellschaft: Bvblingen
> Registergericht: Amtsgericht Stuttgart, HRB 243294

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