This would be easy to solve once the problem is defined precisely.

At the moment it isn't.

For example:

> I want to count the number of classes that reference a set of sources,
> e.g., "XYZ and VWX", via <source-assoc/> or <reqt-assoc/> tags
> ****** Desired output for XYZ and VWX *******
> 5
> *****************************

No. The answer is 0. There isn't even a single class that references both 
XYZ and VWX.

Probably you meant "XYZ or VWX"


For now -- just guessing -- what you most probably want is something like 
this:

count(/*/*/class
                [descendant::*
                     [ @source = 'XYZ'
                    or @source='VWX'
                    or starts-with(@reqt, 'XYZ-')
                    or starts-with(@reqt, 'VWX-')
                      ]
                 ]
         )


which in your example eveluates to 5.

Constructing such an expression is trivial with the XPath Visualizer (took 
less than a minute).


Cheers,
Dimitre Novatchev.

<drs58@m...> wrote in message 
news:1118786787.715013.15570@g......
Same as before but with a root node 'model':


****** Sample XML *******
<model>
  <source id="VWX" description="This is VWX"/>
  <source id="WXY" description="This is WXY"/>
  <source id="XYZ" description="This is XYZ"/>
  <reqt id="VWX-01" description="This is a requirement identified
within
  source VWX"/>
  <reqt id="XYZ-01" description="This is a requirement identified
within
  source XYZ"/>
  <reqt id="XYZ-02" description="This is another requirement identified

  within source XYZ"/>
  <package name = "pkg01">
    <class name="ABC">
      <source-assoc source="XYZ"/>
    </class>
    <class name="BCD">
      <reqt-assoc reqt="XYZ-01"/>
    </class>
    <class name="CDE">
      <source-assoc source="XYZ"/>
      <reqt-assoc reqt="XYZ-01"/>
      <reqt-assoc reqt="XYZ-02"/>
    </class>
    <class name="DEF">
      <reqt-assoc reqt="VWX-01"/>
    </class>
    <class name="EFG">
      <reqt-assoc reqt="XYZ-02"/>
    </class>
    <class name="FGH">
      <source-assoc source="WXY"/>
    </class>
  </package>
</model>
*****************************


I want to count the number of classes that reference a set of sources,
e.g., "XYZ and VWX", via <source-assoc/> or <reqt-assoc/> tags
****** Desired output for XYZ and VWX *******
5
*****************************


My approach is to:
1) construct a variable with all source document id's concatenated and
delimited by '*', e.g.,
  <xsl:variable name="source-ids">*VWX*WXY*XYZ­*</xsl:variable>


2) for each class, construct a variable by iterating through the
classes and adding a character, e.g., 'X',
   every time I find a one with an appropriate <source-assoc> or
<reqt-assoc/> tag, e.g.,
  <xsl:variable name="related-classes">
     <xsl:for-each select="package/class">
         <


xsl:if test=".//source-assoc[contains­($source-ids, '*' +
@source + '*')] | .//reqt-assoc[contains($source­-ids, '*' +
substring-before(@reqt, '-') + '*')]">X</xsl:if>
     </xsl:for-each>
  </xsl


:variable>
  NOTE: I want to include the delimiter in the contains function
parameter to ensure that the match is not based on a substring within a

source id
  NOTE: The <source-assoc/> and <reqt-assoc/> tags might actually also
be included within elements contained within classes.

3) display string-length($related-classes­)


Problem: I don't believe "'*' + @source + '*'" is being processed
correctly within the contains function.