RE: [xsl] selecting a parameter using string expression?

[TSchutzerWeissmann at uk dot imshealth dot com]

Hi Mattias,

> > How about having only one parameter containing name:value pairs,
> > and make an adapted tokeniser to turn it into a node-set? That way
> > you could use XPath on your parameters to find out which ones they
> > are as well as what value they have.
> >
> > Just a suggestion - I haven't completely got my head round 
> your problem
> > so maybe I'm missing the wood for a tree or 2.
> > Tom
> 
> Well it sounds good, but how do you do an adapted tokenizer? 
> Must confess I
> haven't done that before :) Could you give an example?

well, if you wanted to do just use xslt you could try this. It's based on
Jeni's str.tokenize.template.xsl
(http://www.exslt.org/str/functions/tokenize/str.tokenize.template.xsl).

I'm not sure how quick it is though.

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
  xmlns:msxsl="urn:schemas-microsoft-com:xslt" 
  extension-element-prefixes="msxsl">

  <xsl:output method="html" encoding="utf-8"/>

  <xsl:param name="paras" select="/.."/>
  <!-- this is the raw list of parameters, a series
       of n : v pairs internally separated by ':' 
       and delimited by '#'s -->
  <!-- each pair will become a param element, 
       whose text value is v and whose name
       attribute is n -->
  

  <!-- turn paras into xml -->
     <xsl:variable name="convertParams">
       <xsl:call-template name="getParams">
        <xsl:with-param name="pList" select="$paras"/>
        <xsl:with-param name="delimiter" select="'#'"/>
        <xsl:with-param name="splitter" select="':'"/>
      </xsl:call-template>
    </xsl:variable>

    <!-- get a node-set of param elements -->
    <xsl:variable name="params" select="msxsl:node-set($convertParams)"/>
    
    <xsl:template name="getParams">
      <xsl:param name="pList" select="/.."/>
      <xsl:param name="delimiter" select="/.."/>
      <xsl:param name="splitter" select="/.."/>
      <xsl:choose>
        <xsl:when test="not($delimiter) or not($splitter)"/>
        <xsl:when test="contains($pList, $delimiter)">
          <xsl:if test="not(starts-with($pList, $delimiter))">
            <xsl:call-template name="getParams">
              <xsl:with-param name="pList" select="substring-before($pList,
$delimiter)" />
                <xsl:with-param name="delimiter" select="$delimiter"/>
                <xsl:with-param name="splitter" select="$splitter"/>
              </xsl:call-template>
            </xsl:if>
            <xsl:call-template name="getParams">
              <xsl:with-param name="pList" select="substring-after($pList,
$delimiter)" />
                <xsl:with-param name="delimiter" select="$delimiter"/>
                <xsl:with-param name="splitter" select="$splitter"/>
              </xsl:call-template>
            </xsl:when>
            <xsl:otherwise>
              <param name="{substring-before($pList,$splitter)}">
                <xsl:value-of select="substring-after($pList,$splitter)"/>
              </param>
            </xsl:otherwise>
          </xsl:choose>
        </xsl:template>
            
        <xsl:template match="/">
          <xsl:for-each select="$params/param">
            <p><xsl:value-of select="@name"/> is <xsl:value-of
select="."/></p>
          </xsl:for-each>
        </xsl:template>

      </xsl:stylesheet>

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