str:concat spacers

Curious, but is there any reason that str:concat doesn't support (nodeset,string?) so that a string can be inserted between all elements? (ala php's implode()). It would effectively eliminate constructions like:

<xsl:for-each select="$list"><xsl:if test="position()!=1">,</xsxl:if><xsl:value-of select="." /></xsl:for-each>

I guess this isn't something that could ever change at this point though.

Foxy