Dongling,
Sorry, I just realized what the problem was.

Dongling had written:
> > Lars,
> > 
> > I works fine except for the following line:
> > 
> > 
> > <xsl:variable name="next-is-child" select=
> >      "//hierarchy/node[parent = Label and child =
> > $next/Label]" />
> > 
> > The expression "parent = Label and child =
> > $next/Label" doesn't work.
> >
> > I have to assign them to
> > variables first:
> > 
> >  xsl:variable name="valueOfParent" select="Label"/>
> >  <xsl:variable name="valueOfChild"
> > select="$next/Label"/>

The problem is I wasn't thinking straight about the context
node inside the [] predicate.

You could use instead:

<xsl:variable name="next-is-child" select=
     "//hierarchy/node[parent = current()/Label and child =
 $next/Label]" />

Or your method of using a variable for valueOfParent is fine too.

Lars


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