Question

I have this xslt :

<xsl:param name="total_articles" select="3" />
<xsl:param name="articles_per_page" select="3" />

<xsl:apply-templates select="dagboek/entry[position &gt; $offset][position &lt; $articles_per_page+$offset]" >
   <xsl:with-param name="total_pages" tunnel="yes">
  <xsl:choose>
          <xsl:when test="$value="2005-09" and $page="1">8</xsl:when>
         <xsl:otherwise>floor(number($total_articles)-1) div $articles_per_page +1</xsl:otherwise>
  </xsl:choose>
  </xsl:with-param>
</xsl:apply-templates>

But now I get this error.

How can I calculate the outcome of the calculation and put it into the param total_pages.

Roelof

Edit 1: WHat I try to achieve is that if it’s not 2005-09 and page is not 1 then the totalpages is calculated out of total_articles and articles_per_page. The outcome has to be put into the param pages.

Answer 1

<xsl:when test="$value="2005-09" and $page="1">8</xsl:when>

This isn’t even well-formed XML document. The problem is with the nested quotes.

Probably you meant:

<xsl:when test="$value='2005-09' and $page='1' ">8</xsl:when>

Another possible problem: Tunnel parameters are only available in XSLT 2.0. You seem to be using XSLT 1.0

Update:

The OP in a comment has modified/clarified his initial question:

WHat I try to achieve is that if it’s not 2005-09 and page is not 1
then the totalpages is calculated out of total_articles and
articles_per_page. The outcome has to be put into the param pages.

This can simply be expressed as:

   <xsl:with-param name="total_pages" select=
    "8*($value='2005-09' and $page='1')
    +
     (floor(number($total_articles)-1) div $articles_per_page +1)
    *
     not($value='2005-09' and $page='1')
    "/>

Explanation:

We are using the fact that in XPath 1.0 by definition number($someBoolean) is 1 if $someBoolean is true() and is 0 if $someBoolean is false().

Therefore the pseudocode:

 if($vCond)
  then $vNum1
  else $vNum2

can be expressed with a single XPath expression:

$vNum1*$vCond + $vNum2*not($vCond )

whenever a boolean is an argument to an arithmetic operator, it is automatically converted to a number.

So, here’s what happens at run-time:

1. Suppose $vCond is true(), therefore not($vCond) is false().

2. Because $vCond and not($vCond) are arguments to the * operator, they are converted to numbers, respectively 1 and 0:

…

$vNum1*1 + $vNum2*0

1. This is equivalent to:

…

$vNum1*1

Note:

The above equivalence rule can be further generalized to N mutually exclusive conditions $vCond1, $vCond2, …, $vCondN, and corresponding N values: $val1, $val2, …, $valN:

$val1*$vCond1 + $val2*$vCond2 + ... + $valN*$vCondN

is equal to $valK (k in {1,..., N}) exactly when $vCondK is true()