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RE: [xsl] Calculating cumulative values

2007-02-04 16:56:08
Thank you for the very helpful explanation Dimitre. 

-----Original Message-----
From: Dimitre Novatchev [mailto:dnovatchev(_at_)gmail(_dot_)com] 
Sent: February 4, 2007 3:41 PM
To: xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com
Subject: Re: [xsl] Calculating cumulative values

On 2/4/07, Simon Shutter <simon(_at_)schemax(_dot_)com> wrote:
Does this dependence on the implementations of the processor mean that
xxx:node-set() is limited to server-side processing or client-side 
where the environment is guaranteed?

If by client-side you mean inside IE, then you have to use the
msxsl:node-set() extension function (where msxsl is bound to the
namespace: "urn:schemas-microsoft-com:xslt"), because IE uses internally
MSXML (3) and at this date none of the MSXML engines implements EXSLT.

It was announced recently that Firefox 3 will implement a subset of EXSLT,
including the node-set() extension.

In case you are using MSXML4, you could use also my implementation of a
subset of EXSLT (described at:
http://www.xml.com/pub/a/2003/08/06/exslt.html)

For the .NET XSLT processors there is a full EXSLT implementation produced
by Dare Obasanjo, Oleg Tkachenko and partly (the Sets
functions) by me. It can be found at Oleg's site (tkachenko.com).

As one can see, the main idea of EXSLT was to provide a portable set of
extensions, however the degree of completeness of their implementation and
the availability using different XSLT processors makes using EXSLT not that
straightforward...

Compare with a library of functions written entirely in XSLT, thus by
definition available on any compliant XSLT processor (really, I am speaking
about XSLT 2.0 here!) and easily extensible (and thus much more powerful) by
anyone, without the need for permissions, agreements and long debates.



Also, I read on http://www.tkachenko.com/blog/archives/000559.html 
that msxsl and exsl are equivalent - if so, should I then use exsl in 
the .net 2.0 environment?

Oleg does not sy this, he says that exsl:node-set() is implemented. I cannot
comment on this, however it is often recommended not to depend on
undocumented features.


--
Cheers,
Dimitre Novatchev
---------------------------------------
Truly great madness cannot be achieved without significant intelligence.
---------------------------------------
To invent, you need a good imagination and a pile of junk
-------------------------------------
You've achieved success in your field when you don't know whether what
you're doing is work or play




[Note to self  :  RTF = result tree fragment - hey, I'm on a very steep
curve here!]

-----Original Message-----
From: Simon Shutter [mailto:simon(_at_)schemax(_dot_)com]
Sent: February 4, 2007 12:11 PM
To: xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com
Subject: RE: [xsl] Calculating cumulative values

Thanks, Dimitre - I'll try that

-----Original Message-----
From: Dimitre Novatchev [mailto:dnovatchev(_at_)gmail(_dot_)com]
Sent: February 4, 2007 7:20 AM
To: xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com
Subject: Re: [xsl] Calculating cumulative values

If I needed to sort the data before I determined the cumulative
numbers, how do I ensure this happens before aggregating the data?

This is a well-known technique, which requires the use of (in your case
msxsl:node-set() ) the extension function exsl:node-set() or the
XSLT-processor-implemented xxx:node-set() extension function.

A smal blueprint is below:

 <xsl:variable name="vrtfOtputTree">
     <!-- Whatever processing required to produce a new tree -->
 </xsl:variable>

 <xsl:variable name="vOutputTree" select="xxx:node-set($vrtfOtputTree)"/>

<!-- Then continue with using the temporary tree that was obtained from
the
RTF -->

  <!-- For example: -->

  <xsl:value-of select="$vOutputTree/*/*[1]"/>

Of course, one can use FXSL for XSLT 1.0 and use the same approach, shown
in
the FXSL 2.0 solution.


--
Cheers,
Dimitre Novatchev
---------------------------------------
Truly great madness cannot be achieved without significant intelligence.
---------------------------------------
To invent, you need a good imagination and a pile of junk
-------------------------------------
You've achieved success in your field when you don't know whether what
you're doing is work or play



On 2/3/07, Simon Shutter <simon(_at_)schemax(_dot_)com> wrote:
I think I may go with 'conventional' solution provided by Andrew,
because
it
is natively supported by .Net 2 and my data sets are relatively small
and tranformed pretty quickly.  I will look more into FXSL for the
longer
term.

If I needed to sort the data before I determined the cumulative
numbers,
how
do I ensure this happens before aggregating the data?

Thanks,

Simon


-----Original Message-----
From: Dimitre Novatchev [mailto:dnovatchev(_at_)gmail(_dot_)com]
Sent: February 3, 2007 4:48 PM
To: xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com
Subject: Re: [xsl] Calculating cumulative values

On 2/3/07, Simon Shutter <simon(_at_)schemax(_dot_)com> wrote:
Thanks, Dimitre.

Two questions -

a) Will this work with .Net 2.0?

No, the two XSLT processors that come as part of  .NET 2.0 (the
classes XslTransform and XslCompiledTransform) only support XSLT 1.0.

However, in a .NET environment one can use Saxon.NET, which is a port
of Saxon 8.x and implements XSLT 2.0.



b) What are the external files : func-scanlDVC.xsl and
func-Operators.xsl?

They are part of the FXSL library.

The latest version of FXSL can be checked out from the CVS of the
project
at:

  http://sourceforge.net/cvs/?group_id=53841


One can learn more about FXSL from the presentations made at the
Extreme Markup Languages Conference in Montreal 2006 (FXSL 2 -- for
XSLT 2.0, and FXSL 1 -- for XSLT 1.0) here:




http://www.idealliance.org/papers/extreme/proceedings/xslfo-pdf/2006/Novatch
ev01/EML2006Novatchev01.pdf

and here:




http://www.idealliance.org/papers/extreme/proceedings/xslfo-pdf/2003/Novatch
ev01/EML2003Novatchev01.pdf


Other papers about different important features of FXSL can be found
at
the
home page of FXSL:

  http://fxsl.sf.net



--
Cheers,
Dimitre Novatchev
---------------------------------------
Truly great madness cannot be achieved without significant intelligence.
---------------------------------------
To invent, you need a good imagination and a pile of junk
-------------------------------------
You've achieved success in your field when you don't know whether what
you're doing is work or play






Simon

-----Original Message-----
From: Dimitre Novatchev [mailto:dnovatchev(_at_)gmail(_dot_)com]
Sent: February 3, 2007 2:50 PM
To: xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com
Subject: Re: [xsl] Calculating cumulative values

On 2/3/07, Andrew Welch <andrew(_dot_)j(_dot_)welch(_at_)gmail(_dot_)com> 
wrote:


You can just use XPath here, no need for recursion:

<xsl:template match="point">
 <xsl:copy>
  <xsl:copy-of select="@*"/>
  <xsl:attribute name="y2">
    <xsl:value-of select="sum(./@y1|preceding-sibling::point[(_at_)x =
current()/@x]/@y1)"/>
  </xsl:attribute>
 </xsl:copy>
</xsl:template>


However evaluating this XPath expression repeatedly is O(N^2) and
will probably be slow for long lists.

Here is a solution, using the FXSL function

     f:scanl1()

This transformation:

<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
 xmlns:f="http://fxsl.sf.net/";
 exclude-result-prefixes="f"

 <xsl:import href="../f/func-scanlDVC.xsl"/>  <xsl:import
href="../f/func-Operators.xsl"/>

 <!-- To be applied on testFunc-scanlDVC3.xml -->  <xsl:output
omit-xml-declaration="yes" indent="yes"/>


 <xsl:template match="node()|@*">
   <xsl:copy>
     <xsl:apply-templates select="node()|@*"/>
   </xsl:copy>
 </xsl:template>

 <xsl:template match="set">
   <xsl:copy>
     <xsl:copy-of select="@*"/>
     <xsl:for-each-group select="point" group-by="@x">
        <xsl:for-each select="f:scanl1(f:add(), current-group()/@y1)">
           <point x="{current-group()[1]/@x}" y="{.}"/>
        </xsl:for-each>
    </xsl:for-each-group>
   </xsl:copy>
 </xsl:template>
</xsl:stylesheet>

When applied against the originally provided xml document:

<root id="theroot">
       <set id="1">
               <point x="1" y1="2" />
               <point x="1" y1="3" />
               <point x="1" y1="0" />
               <point x="1" y1="2" />
               <point x="1" y1="2" />
               <point x="2" y1="3" />
               <point x="2" y1="0" />
               <point x="2" y1="2" />
               <point x="3" y1="2" />
               <point x="3" y1="3" />
               <point x="3" y1="1" />
               <point x="3" y1="2" />
               <point x="3" y1="2" />
       </set>
       <set id="2">
               <point x="1" y1="2" />
               <point x="1" y1="3" />
               <point x="1" y1="0" />
               <point x="1" y1="2" />
               <point x="2" y1="2" />
               <point x="3" y1="2" />
               <point x="3" y1="2" />
               <point x="3" y1="2" />
       </set>
       <set id="n">
               <point x="1" y1="2" />
               <point x="1" y1="3" />
               <point x="1" y1="2" />
               <point x="2" y1="3" />
               <point x="2" y1="0" />
               <point x="2" y1="2" />
               <point x="3" y1="3" />
       </set>
</root>

produces the wanted result:

<root id="theroot">
  <set id="1">
     <point x="1" y="2"/>
     <point x="1" y="5"/>
     <point x="1" y="5"/>
     <point x="1" y="7"/>
     <point x="1" y="9"/>
     <point x="2" y="3"/>
     <point x="2" y="3"/>
     <point x="2" y="5"/>
     <point x="3" y="2"/>
     <point x="3" y="5"/>
     <point x="3" y="6"/>
     <point x="3" y="8"/>
     <point x="3" y="10"/>
  </set>
  <set id="2">
     <point x="1" y="2"/>
     <point x="1" y="5"/>
     <point x="1" y="5"/>
     <point x="1" y="7"/>
     <point x="2" y="2"/>
     <point x="3" y="2"/>
     <point x="3" y="4"/>
     <point x="3" y="6"/>
  </set>
  <set id="n">
     <point x="1" y="2"/>
     <point x="1" y="5"/>
     <point x="1" y="7"/>
     <point x="2" y="3"/>
     <point x="2" y="3"/>
     <point x="2" y="5"/>
     <point x="3" y="3"/>
  </set>
</root>


--
Cheers,
Dimitre Novatchev
---------------------------------------
Truly great madness cannot be achieved without significant
intelligence.
---------------------------------------
To invent, you need a good imagination and a pile of junk
-------------------------------------
You've achieved success in your field when you don't know whether
what you're doing is work or play

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