Re: [xsl] Incrementing a Global variable

[Bill Keese <billk@xxxxxxxxxxxxxxxxxxxx>]

(this is a resend; my original message bounced, I think)

Problem: print a list of students, grouping the students by their 
language and printing a blank line between each group.  Number the blank 
lines in addition to the lines with students' names.

So calling position() to get the number is insufficient, because 
position() doesn't count the blank lines.

Mukul was commenting that this problem would be easier to solve if XSLT 
supported something like variables. For example:

 <xsl:for-each select="Student">
      <xsl:if test="TOption != previous-sibling::Student[last()]/TOption">
           <tr> <td> {counter} </td>  <td/> <td/> </tr>
           counter++;
      </xsl:if>

      <tr> <td> {counter} </td>  <td> {Name} </td> <td> { Toption } 
</td> </tr>
      counter++;
  </xsl:for-each>

This is what Jarno's code essentially does, but Jarno had to use 
recursion to simulate the loop, which is [arguably] a bit cumbersome.  
However, you can do something the loop above, if you replace the 
variable "counter" with a formula, which is
 the previous number of students + the previous number of groups

In XSLT version 2 this is simply:

count(preceding-sibling::*) + 
count(distinct-values(preceding-sibling::*/TOption/text()))

And after the loop finishes, to compute the total number of lines 
printed, you would do

count(Student) + count(distinct-values(Student/TOption/text()))

-------------
By the way, an alternative to a single loop is to write a nested loop 
(for-each language / for-each student).  This is what Americo's code 
does, but his code is a bit complicated because he is programming in 
XSLT V1, where there is no for-each-group operator 
(http://www.w3.org/TR/xslt20/#d0e15262) .  But in XSLT V2 we would say this:

   <xsl:for-each-group select="Student" group-by="TOption">
     <xsl:variable name="group-no" select="position()"/>
     <xsl:for-each select="current-group()">
       <tr>
         <td> <xsl:value-of select="count(preceding-sibling::*) + 
$group-no"/> </td>
         <td> <xsl:value-of select="Name"/> </td>
         <td> <xsl:value-of select="TOption"/> </td>
       </tr>
     </xsl:for-each>
     <tr>
       <td> <xsl:value-of 
select="count(current-group()[last()]/preceding-sibling::*) + $group-no 
+ 1"/> </td>
       <td>  </td>
       <td>  </td>
     </tr>
   </xsl:for-each-group>

Bill


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