This can be done with Muenchian grouping...

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
	
<xsl:key name="by-id" match="*" use="@id" />
	
<xsl:template match="/">
   <uniques>
      <xsl:for-each select="//*[@id][generate-id(.) = 
generate-id(key('by-id', @id)[1])]">
          <unique id="{@id}" type="{../@type}" />
       </xsl:for-each>
   </uniques>
</xsl:template>
	
</xsl:stylesheet>

Regards,
Mukul

"Daniel" wrote:

> Using code i pull values from xml and put it into a hashes then put it back
> into xml to get the unique set. However, I was wondering if this was
> possible via xsl:
> 
> ___________________________________________________
> <foo>
>        <bars type="bartype">
>             <bar id="1" x="a1" y="a2" z="3"/>
>             <bar id="2" x="a11" y="a22" z="33"/>
>             <bar id="1" x="a11111" y="a22222" z="33333"/>
>         </bars>
>         <houses type="housetype">
>             <house id="7" a="a1" b="a2" c="a3"/>
>             <house id="8" a="a1" b="a2" c="a3"/>
>             <house id="9" a="a1" b="a2" c="a3"/>
>         </houses>
>        <bars type="bartype">
>             <bar id="2" x="a111" y="a222" z="a333"/>
>             <bar id="1" x="a1111" y="a2222" z="a3333"/>
>         </bars>
> </foo>
> ___________________________________________________
> to
> ___________________________________________________
> <uniques>
>     <unique id="1" type="bartype"/>
>     <unique id="2" type="bartype"/>
>     <unique id="7" type="housetype"/>
>     <unique id="8" type="housetype"/>
>     <unique id="9" type="housetype"/>
> </uniques>
> ___________________________________________________
> 
> 
>