Re: building a hierarchical classification out of flat

> Davids approach works with the sample data, but in my real data there
> is no consistent sequence of numbers inside the names of the tags that
> you could use to "count" the level. So although it is a very nice
> approach, the "$level+1"-mechanism doesn't work for me.

There are modifications you can do, so if the structure is the same but
instead of  tag1 tag2  tag3 you have  blue red green then
you could have something like
<xsl:variable name="names" select="('blue','red','green')"/>
then replace 

*[name()=concat('tag',$level)]

by

*[name()=$names[$level]]

etc...
David