Reassign param value?

victorcorey · November 28th, 2007, 04:02 PM

I am trying to test a node value and if it changes I want to change a param value?

Somthing like this:

Code:

<xsl:param name="CurrentState" />
<xsl:for-each select="row">
   <xsl:choose>
      <xsl:when test="$CurrentState = ''">
         <xsl:param name="CurrentState" select="state" />
         <xsl:value-of select="$CurrentState" />
      </xsl:when>
      <otherwise>
         <xsl:if test="$CurrentState != state">
            <xsl:param name="CurrentState" select="state" />
            <xsl:value-of select="$CurrentState" />
         </xsl:if>
      </otherwise>
   </xsl:choose>
</xsl:for-each>

Basically, I have a node called state that is duplicated throughout the row node. I want to only show this once. So my thought is if the CurrentState param is null, assign the state node value to it and display it. Otherwise if the CurrentState param does not equal the state node then assign the value and display. If neither of these conditions are true don't display the state.

I'm new to XSLT if you cant tell.

Thanks,
Victor

--
Victor Corey

samjudson · November 29th, 2007, 04:49 AM

You're obviously aware by now that you can't do what you are trying to do, as you can't change the value of a variable or parameter in XSLT.

If you let us know why you are trying to do this then we can probably advise on an alternative method of doing what you want to do.

/- Sam Judson : Wrox Technical Editor -/

mhkay · November 29th, 2007, 05:33 AM

XSLT is a functional language, and the methods that you used in the past with procedural languages don't always apply. In particular, you can't update variables, and you can't do anything when processing one item in a for loop that affects the way "subsequent" items are processed, because there's no concept of "subsequent" - you have to imagine they are all processed in parallel.

If the number of rows is small, you can do

<xsl:if test="not(state = preceding-sibling::row/state)"

If you're using XSLT 2.0 you probably want to be using xsl:for-each-group or the distinct-values() function.

If you're using XSLT 1.0 (and there's no way you can upgrade) then look at the various grouping techniques discussed at http://www.jenitennison.com/xslt/grouping. They aren't easy, but you get the hang of them.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference