Use position of current node to access value of another node - xpath

Question

I have an xml source that approximates a table layout (output from a program) - a is the table holder, b hold the column headings d, c are the rows and e are the row cells:
<?xml version="1.0" encoding="utf-16"?>
<a>
<b>
<d/>
<d/>
<d/>
</b>
<c>
<e/>
<e/>
<e/>
</c>
</a>
</xml>
I have written the following xsl:
<?xml version="1.0" encoding="UTF-16"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" >
<xsl:template match="/">
<Lessons>
<xsl:for-each select="//c">
<xsl:call-template name="lesson" />
</xsl:for-each>
</Lessons>
</xsl:template>
<xsl:template name="lesson">
<Lesson>
<Teacher>
<xsl:value-of select="count(./preceding-sibling::*)+1" />
<xsl:value-of select="//b[count(./preceding-sibling::*)+1]" />
</Teacher>
</Lesson>
</xsl:template>
</xsl:stylesheet>
The first xsl:value-of of the Teacher element gives me the correct values. I would like the second xsl:value-of to return the value of the heading for that cell i.e. for the first e element that calls the template the first d element is returned and so on. However, it ouputs the value of all of the d elements.

Answer 1

Even if it is not entirely clear what you expect, I will try an answer.
As I understood you like to find the <d> element which has the same position than the <e> element.
This is either possible with getting the current position as a variable.
xsl:variable name ="pos" select="position()" />
<xsl:value-of select="//b/d[position() = $pos]/#id" />
or use count of preceding-sibling
<xsl:value-of select="//b/d[(count(current()/preceding-sibling::*)+1)]/#id" />
Update the part below is changed because of the comment from "George of all trades".
Be aware that the result of position()depends on the calling context.
For example following test xslt (version 1.0):
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" >
<xsl:output method="xml" indent="yes"/>
<xsl:template match="/">
<Lessons>
<!-- Wrong result with position -->
<xsl:for-each select="//c/e">
<xsl:call-template name="lesson" />
</xsl:for-each>
</Lessons>
<Lessons2>
<!-- Wonted result even with position -->
<xsl:for-each select="//c">
<xsl:for-each select="e">
<xsl:call-template name="lesson" />
</xsl:for-each>
</xsl:for-each>
</Lessons2>
</xsl:template>
<xsl:template name="lesson">
<Lesson>
<Teacher>
<xsl:value-of select="#id" />
<xsl:text>,</xsl:text>
<xsl:value-of select="count(./preceding-sibling::*)+1" />
<xsl:text>,</xsl:text>
<xsl:variable name ="pos" select="position()" />
<xsl:value-of select="$pos" />
<xsl:text>,</xsl:text>
<xsl:value-of select="//b/d[position() = $pos]/#id" />
<xsl:text>,</xsl:text>
<xsl:value-of select="//b/d[count(current()/preceding-sibling::*)+1]/#id" />
</Teacher>
</Lesson>
</xsl:template>
</xsl:stylesheet>
With this input:
<?xml version="1.0" encoding="utf-16"?>
<xml>
<a>
<b>
<d id="d1"/>
<d id="d2"/>
<d id="d3"/>
</b>
<c>
<e id="e1"/>
<e id="e2"/>
<e id="e3"/>
</c>
<c>
<e id="e21"/>
<e id="e22"/>
<e id="e23"/>
</c>
<c>
<e id="e21"/>
<e id="e22"/>
<e id="e23"/>
</c>
</a>
</xml>
Generates this output:
<Lessons>
<Lesson>
<Teacher>e1,1,1,d1,d1</Teacher>
</Lesson>
<Lesson>
<Teacher>e2,2,2,d2,d2</Teacher>
</Lesson>
<Lesson>
<Teacher>e3,3,3,d3,d3</Teacher>
</Lesson>
<Lesson>
<Teacher>e21,1,4,,d1</Teacher>
</Lesson>
<Lesson>
<Teacher>e22,2,5,,d2</Teacher>
</Lesson>
<Lesson>
<Teacher>e23,3,6,,d3</Teacher>
</Lesson>
<Lesson>
<Teacher>e21,1,7,,d1</Teacher>
</Lesson>
<Lesson>
<Teacher>e22,2,8,,d2</Teacher>
</Lesson>
<Lesson>
<Teacher>e23,3,9,,d3</Teacher>
</Lesson>
</Lessons><Lessons2>
<Lesson>
<Teacher>e1,1,1,d1,d1</Teacher>
</Lesson>
<Lesson>
<Teacher>e2,2,2,d2,d2</Teacher>
</Lesson>
<Lesson>
<Teacher>e3,3,3,d3,d3</Teacher>
</Lesson>
<Lesson>
<Teacher>e21,1,1,d1,d1</Teacher>
</Lesson>
<Lesson>
<Teacher>e22,2,2,d2,d2</Teacher>
</Lesson>
<Lesson>
<Teacher>e23,3,3,d3,d3</Teacher>
</Lesson>
<Lesson>
<Teacher>e21,1,1,d1,d1</Teacher>
</Lesson>
<Lesson>
<Teacher>e22,2,2,d2,d2</Teacher>
</Lesson>
<Lesson>
<Teacher>e23,3,3,d3,d3</Teacher>
</Lesson>
</Lessons2>