something like :
 
<xsl:template match="plants">
  <xsl:for-each select="plant" order-by="plant[@color]"> 
   <xsl:variable name="currentColor"><xsl:value-of
select="@color"/></xsl:variable>
   <xsl:if
test="count(from-preceding-siblings(plant[@color=$currentColor]))=0">
    <plant>
     <xsl:attribute name ="color">
      <xsl:value-of select="@color"/>
     </xsl:attribute>
     <xsl:value-of select="."/>
    </plant>
   </xsl:if>
  </xsl:for-each> 
  </xsl:template>
 
is supposed to read in something that looks like :
 
<plants>
    <plant color="red">Rose1</plant>
    <plant color="blue">Rose2</plant>
    <plant color="red">Rose3</plant>
    <plant color="green">Rose4</plant>
    ...
 
and output a list of plants omitting the ones of which the
color occurred before.
 
Juliane Harbarth


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list