xsl:perform-sort (in 2.0)

I just noticed this new instruction (although it was in the last draft
as well)

Is there any difference bewteen

  <xsl:perform-sort select="$in">
    <xsl:sort select="."/>
  </xsl:perform-sort>

and

  <xsl:for-each select="$in">
    <xsl:sort select="."/>
    <xsl:copy-of select="."/>
  </xsl:for-each>

either from a definitional or efficiency point of view?

David


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