[xsl] counting elements with values that match other element values

[Sean Whalen <seanwhalen@xxxxxxxxxxx>]

    I step away from xpath and xslt for long stretches, and when I come 
back, parts of the big picture are a little fuzzy.  My sense is that for 
the problem below, I need to loop; the test can't be done in a single 
XSLT1.0 statement. 
  
   I have a set of elements ("t") with children under them 
("t/cSet/c").  I'm looking for children that occur twice.  I'd like get 
a nice 1.0 nodeset, which is the practical reason for trying to shoehorn 
the task into a single statement. 

   The xslt and xml are below.  I used command-line saxon for debugging. 

   The expression for the element "Find_Cs_In_Ts" is what I'd like to 
either get working, or get an official confirmation that the task is 
impossible.  In the real implementation the "> 0" would be " = 2", 
and the answer would be "3, 5, and 7", which are the numbers that occurs 
twice in the set.  The other elements are just me playing around with 
similar constructions that return related data. 

   In SQL, this would be something like
                           select * from ccc where (select count (*) 
from T/cSet as TC  where tc.c = ccc.c ) >0

   Any explanation for what the right syntax is, or, conceptually, why 
the idea doesn't fit in with xslt1.0 would be greatly appreciated.  I've 
got looping code for the task almost implemented, so, mostly I'm asking 
for how the parser is reading the expression I wrote, and how far away 
is what I wrote from what I really wanted? 

   Another approach might be to use the parent axis to walk back up and 
then over to other T elements to find the related data.  

thanks for any suggestions,


======================
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"; 
xmlns:xs="http://www.w3.org/2001/XMLSchema";>

<xsl:output method="html"/>

<xsl:template match="/">
                                   
   <xsl:call-template name="make-Choices">
    </xsl:call-template>

</xsl:template>

<xsl:template name = "make-Choices">

<xsl:variable  name = "output"  >
      <xsl:element name="root">
      
      <xsl:element name = "ccc"><xsl:copy-of select="root/ccc/*"/> 
</xsl:element> 

   <xsl:element name = "Find_Cs_In_Ts"><xsl:copy-of select="
       //root/ccc/c[ count(  //root/t[  h =1  and  . =   cSet/c    ]   
) &gt; 0     ] "/> </xsl:element> 


   <xsl:element name = "Count7s_In_TH"><xsl:copy-of select="
         count(  //root/t[  h =1  and    cSet/c  = 7   ]   )   "/> 
</xsl:element> 

      <xsl:element name = "Cs_In_Ts"><xsl:copy-of select="
       //root/ccc/c[  . =  //root/t[  h =1    ]/cSet/c   ]      "/> 
</xsl:element> 


      <xsl:element name = "Count_TCs_In_C"><xsl:copy-of select="count( 
root/t[h =1]/cSet/c[. =  //root/ccc/c]  ) "/> </xsl:element>    
 </xsl:element>   
</xsl:variable>   

 <xsl:copy-of select="$output"/>

</xsl:template>


</xsl:stylesheet>

============
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="ukbSmall.xslt"?>
<root>
  <ccc>
     
<c>1</c><c>2</c><c>3</c><c>4</c><c>5</c><c>6</c><c>7</c><c>8</c><c>9</c>
  </ccc>
  <t>
     <h>1</h><v>3</v>
     <cSet><c>3</c><c>5</c><c>8</c></cSet>
  </t>   
  <t>
     <h>1</h><v>4</v>
     <cSet><c>3</c><c>5</c></cSet>
  </t>
  <t>
     <h>1</h><v>7</v>
     <cSet><c>7</c><c>8</c></cSet>
  </t>
  <t>
     <h>1</h><v>9</v>
     <cSet><c>7</c><c>8</c></cSet>
  </t>     
</root>