RE: Filtering out duplicates in current-group()

> <xsl:for-each-group select="Song"
> group-by="substring(Year, 1, 3)">
>   <p>Decade: <xsl:value-of
> select="current-grouping-key()"/>0's</p>
>     <xsl:for-each-group select="current-group()"
> group-by="Title">
> 	<p style="margin-left: 1pc;">
> 	  <xsl:value-of select="current-grouping-key()"/>
> 	</p>
>   </xsl:for-each-group>
> </xsl:for-each-group>
> 
> Why is "value-of" required and "apply-templates"
> illegal?

Neither is required or illegal, they just do different things.

A group contains many nodes (in the current-group()) sharing one
grouping-key. If you process the grouping key you get one thing output, if
you process the current-group you get many things output.

Michael Kay
http://www.saxonica.com/