For instance, say you have a source document like this:
<top>
<a/>
<b/>
<c/>
<d/>
</top>
and the output of "b" depends on the position of "a", "c" depends on "b" and
so on.
Functional languages are good at expressing loops.
<xsl:template name="position">
<!-- get results of previous computations via parameters -->
<xsl:param name="prev-x"/><xsl:param name="prev-y"/>
<!-- compute current values based on the current node and results computed for
the previous one -->
<xsl:variable name="x" select="$prev-x + @width"/>
<xsl:variable name="y" select="$prev-y + @height"/>
<!-- output the current node with the results computed -->
<xsl:copy>
<xsl:copy-of select="@*">
<xsl:attibute name="x"><xsl:value-of select="$x"/></xsl:attribute>
<xsl:attibute name="y"><xsl:value-of select="$y"/></xsl:attribute>
</xsl:copy>
<!-- call the template for the next sibling, if there is one -->
<xsl:for-each select="following-sibling::*[1]">
<xsl:call-template name="position">
<xsl:with-param name="prev-x" select="$x"/>
<xsl:with-param name="prev-y" select="$y"/>
</xsl:call-template>
</xsl:for-each>
</xsl:template>
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list