Update attribute in XSL for-each - pdf

Question

At work I've been given the fun task of generating PDFs with XSL. The XML structure I'm working with is similar to
<records>
<topLevel>
<topLevelID></topLevelID>
<secondLevel>
<secondLevelID></secondLevelID>
<thirdLevel>
</thirdLevel>
<thirdLevel>
</thirdLevel>
</secondLevel>
</topLevel>
<topLevel>
<topLevelID></topLevelID>
<secondLevel>
<secondLevelID></secondLevelID>
<thirdLevel>
</thirdLevel>
<thirdLevel>
</thirdLevel>
</secondLevel>
</topLevel>
</records>
I would try to give a more meaningful example of the XML, but I don't feel like approaching any legal boundaries that may exist. With that XML structure, I have to output a block of text in the PDF for every thirdLevel node. The XSL I have so far is like
<xsl:for-each select ="topLevel">
<xsl:variable name="topID" select="topLevelID"/>
<xsl:for-each select ="secondLevel">
<xsl:variable name="secondID" select="secondLevelID"/>
<xsl:for-each select="thirdLevel">
<fo:block-container position="absolute" height="12.8pt" width="220.8pt" left="160pt" display-align="auto">
<xsl:attribute name="top">
<xsl:value-of select="concat(193 + [whatshouldgohere]), 'pt')"/>
</xsl:attribute>
<fo:block font-size="7pt">
<xsl:call-template name="insertThirdLevel"/>
</fo:block>
</fo:block-container>
</xsl:for-each>
</xsl:for-each>
</xsl:for-each>
Basically, I need to add some value to the top attribute to make the text for each thirdLevel node appear on its own line. I've tried using combinations of adding/multiplying by the ID (starts at 1 and increases by 1 for each set) and position(), but I can't seem to get it right.

Answer 1

I think you should really look into <xsl:apply-templates>, it can save you a lot of typing.
Simplified version:
<xsl:variable name="line-height" select="10" />
<xsl:template match="/records">
<xsl:apply-templates select="//thirdLevel" />
</xsl:template>
<xsl:template match="thirdLevel">
<xsl:variable name="top" select="193 + position() * $line-height" />
<fo:block-container top="{concat($top , 'pt')}">
<fo:block font-size="7pt">
<xsl:call-template name="insertThirdLevel"/>
</fo:block>
</fo:block-container>
</xsl:template>
<xsl:template name="insertThirdLevel">
Third Level!
</xsl:template>
Simplified output ("fo" namespace excluded):
<fo:block-container top="203pt">
<fo:block font-size="7pt">
Third Level!
</fo:block>
</fo:block-container>
<fo:block-container top="213pt">
<fo:block font-size="7pt">
Third Level!
</fo:block>
</fo:block-container>
<fo:block-container top="223pt">
<fo:block font-size="7pt">
Third Level!
</fo:block>
</fo:block-container>
<fo:block-container top="233pt">
<fo:block font-size="7pt">
Third Level!
</fo:block>
</fo:block-container>