Re: [xsl] Re: question on random numbers for browser XSLT

[Hermann Stamm-Wilbrandt <STAMMW@xxxxxxxxxx>]

Dimitre,

> > If you have decided to go with a service providing random numbers then
> > xslt-ish way (set based) to do it would be a service receiving a number
and
> > returning an xml with a specified number of random numbers.
> >
>
> Using a service to provide a random sequence is much more unreliable
> and inefficient than just doing this in pure XSLT, as this has been
> done by FXSL for many years:
>
>
http://fxsl.sourceforge.net/articles/Random/Casting%20the%20Dice%20with%20FXS
L-htm.htm

first of all, FXSL is a cool library and the documentation at the link is
informative.

I tried fxsl-1.2 and installed these necessary files on my webserver:
curry.xsl  iter.xsl  map.xsl  random.xsl  test-random.xsl

First I realized that it did work on FF3 and not on FF2 (because of the
missing
support of exslt:node-set there). Then I tried it on IE6 and it did not
work first.
After applying below patch it worked under IE6, too.
You may try it out here:
http://www.stamm-wilbrandt.de/en/xsl-list/random/fxsl-1.2/test-random.xml

The output is the same as generated by eg. "xsltproc test-random.xsl
some.xml", but
it is ALWAYS THE SAME output (try it repeatedly).

I knew of the different techniques in generating pseudo random numbers but
what
is really needed is to be able to provide a changing seed (eg. initialize
with
the number of seconds since 1/1/1970, time(NULL) in C).

Then I remembered the generate-id use of Scott, and after reading Michaels
last
post the following fragment seems to be an always changing value:
http://www.stamm-wilbrandt.de/en/xsl-list/random/scott.xml

        <xsl:variable name="seed"><a/></xsl:variable>
        <xsl:value-of select="generate-id(exsl:node-set($seed))" />

Now these values look different for different browsers, and need to
"somehow"
be converted to a seed value for FXSLs random generator.

Ideas?


=============================================================================
from "http://dpcarlisle.blogspot.com/2007/05/exslt-node-set-function.html";
$ diff random.xsl.orig random.xsl
20c20,21
<  exclude-result-prefixes="xsl ext randScale myRandNext
mySingleRandDistFun x"
---
>  xmlns:msxsl="urn:schemas-microsoft-com:xslt"
>  exclude-result-prefixes="xsl ext msxsl randScale myRandNext
mySingleRandDistFun x".
30a32,36
>   <msxsl:script language="JScript" implements-prefix="ext">
>     this['node-set'] =  function (x) {
>       return x;
>     }
>   </msxsl:script>
$



Mit besten Gr|_en / Best wishes,

Hermann Stamm-Wilbrandt
Developer, XML Compiler
WebSphere DataPower SOA Appliances
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             Dimitre Novatchev
             <dnovatchev@gmail
             .com>                                                      To
                                       xsl-list@xxxxxxxxxxxxxxxxxxxxxx
             07/24/2009 11:00                                           cc
             PM
                                                                   Subject
                                       Re: [xsl] Re: question on random
             Please respond to         numbers for browser XSLT
             xsl-list@xxxxxxxx
              lberrytech.com








> If you have decided to go with a service providing random numbers then
> xslt-ish way (set based) to do it would be a service receiving a number
and
> returning an xml with a specified number of random numbers.
>

Using a service to provide a random sequence is much more unreliable
and inefficient than just doing this in pure XSLT, as this has been
done by FXSL for many years:


http://fxsl.sourceforge.net/articles/Random/Casting%20the%20Dice%20with%20FXS
L-htm.htm



--
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 Fri, Jul 24, 2009 at 1:48 PM, Vladimir
Nesterovsky<vladimir@xxxxxxxxxxxxxxxxxxxx> wrote:
> If you have decided to go with a service providing random numbers then
> xslt-ish way (set based) to do it would be a service receiving a number
and
> returning an xml with a specified number of random numbers.
> --
> Vladimir Nesterovsky
> http://www.nesterovsky-bros.com/
>
>
>> To Ben:
>> The cache-append idea was my first thought, but I couldn't think of a
>
> good
>>
>> way to pull together how to have each request be unique. It's possible
>> using node-set(), though:
>> ...
>> ...
>>    <xsl:choose>
>>      <xsl:when test="function-available('exsl:node-set')">
>>        <xsl:value-of select="document(concat('/cgi-bin/rand.pl?',
>
> $scale,
>>
>> '&amp;x=', generate-id(exsl:node-set($seed))))" />
>>      </xsl:when>
>>      <xsl:when test="function-available('msxsl:node-set')">
>>        <xsl:value-of select="document(concat('/cgi-bin/rand.pl?',
>
> $scale,
>>
>> '&amp;x=', generate-id(msxsl:node-set($seed))))" />
>>      </xsl:when>
>> ...
>
> I tried your solution and after replacing '&amp;x=' with '+' it directly
> worked on my local web server!
> (I did not know that generate-id works in a browser)
>
> But as already posted it did not work after installed on my real
webserver
> because that does not have enough power to handle the six document opens.
>
> Btw, I really like the solution of David Carlisle to provide
exslt:node-set
> for IE browsers (and not having to deal with exslt/msxml):
> http://dpcarlisle.blogspot.com/2007/05/exslt-node-set-function.html