[xsl] group-by sorting and paging problem...

I've been struggling with this for days. The problem seems simple,  
but I've had no luck...Here's what I'm trying to do:
  -  Group the <msgblocks> by attribute 'id'
  -  Use the current grouping id (@id) to sort the data
  - Arrange the data I want to extract from each sorted <msgblock>  
(errnum and message) into a series of balanced 4 column tables  
limited to a maximum of x number of
     rows, based on the value of the global param $cols
  - Write (or page) each table to a result-document

A subset of the xml looks like this:

<messages>
  <msgblock id="2000">
    <msg-num>0</msg-num>
    <errnum>2000</errnum>
    <message> No message</message>
  </msgblock>

  <msgblock id="2001">
    <msg-num>100</msg-num>
    <errnum>2001</errnum>
    <message> "Row not found"</message>
  </msgblock>

  <msgblock id="2002">
    <msg-num>101</msg-num>
    <errnum>2002</errnum>
    <message> "Value truncated"</message>
  </msgblock>

  <msgblock id="2003">
    <msg-num>102</msg-num>
    <errnum>2003</errnum>
    <message> "Using temporary table"</message>
  </msgblock>

  <msgblock id="2004">
    <msg-num>103</msg-num>
    <errnum>2004</errnum>
    <message> "Invalid data conversion"</message>
  </msgblock>

  <msgblock id="2559">
    <msg-num>130</msg-num>
        <errnum>2559</errnum>
    <message> "A row could not be converted to the new schema  
format"</message>
  </msgblock>

  <msgblock id="2532">
   <msg-num>124</msg-num>
    <errnum>2532</errnum>
    <message> "Invalid data conversion: NULL was inserted for column  
'%1' on line %2."</message>
  </msgblock>

  <msgblock id="2005">
    <msg-num>104</msg-num>
    <errnum>2005</errnum>
    <message> "Row has been updated since last time read"</message>
  </msgblock>

  <msgblock id="2006">
    <msg-num>105</msg-num>
        <errnum>2006</errnum>
    <message> "Procedure has completed"</message>
  </msgblock>

  <msgblock id="2007">
    <msg-num>106</msg-num>
    <errnum>2007</errnum>
    <message> "Value for column '%1' in table '%2' has changed"</ 
message>
  </msgblock>

  <msgblock id="2008">
    <msg-num>111</msg-num>
    <errnum>2008</errnum>
    <message> "Statement cannot be executed"</message>
  </msgblock>

  <msgblock id="2530">
    <msg-num>123</msg-num>
    <errnum>2530</errnum>
    <message> "Database created without any schema"</message>
  </msgblock>

  <msgblock id="2009">
    <msg-num>200</msg-num>
    <errnum>2009</errnum>
    <message> "Warning"</message>
  </msgblock>

  <msgblock id="2011">
    <msg-num>80</msg-num>
    <errnum>2011</errnum>
    <message> "Unable to start database server"</message>
  </msgblock>

  <msgblock id="2702">
    <msg-num>1033</msg-num>
    <errnum>2702</errnum>
    <message> "Unable to start database server: Server fatal error"</ 
message>
  </msgblock>

  <msgblock id="2012">
    <msg-num>81</msg-num>
    <errnum>2012</errnum>
    <message> "Invalid database server command line"</message>
  </msgblock>

</messages>


Grouping and sorting the <msgblock> nodes is necessary because the  
@id's are not always in the right sequence. I can group and sort them  
properly with this snippet:
<xsl:for-each-group select="msgblock" group-by="@id">
                <xsl:sort select="current-grouping-key()"/>
                <for-each select=”current-group()”/>
                        <xsl:value-of select =”errnum”/>
                        <xsl:vale-of select=”message”/>
                </for each>
        <for-each-group>

I can limit the number of table items by testing the global  
parameters $start-index (1) and $group-size (40) with something like  
this:
        <xsl:if test="position() &gt;= $start-index
            and position() &lt;= $group-size">
        .       
        .       
        .
        </xsl:if>

(Thank you, Ms. Tennison)

I can see the logic in Micheal Kay's examples (town-by-columns, town- 
by-rows, towns-sorted-by-rows) in the XSLT 2.0 Programmer's  
Reference. But I can't seem to put them all together. (I always seem  
to end up dividing by zero).  I seemed close a couple of times, but  
I've had no luck. In fact, I seem to be going backwards.
Does anyone know how to do this?

Thanks in advance....

        ------- bob wilkins ------


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