made template match 'pubDate' so it can be called by 'apply-templates', removed redundant substring()s

date-utility_RFC-to-ISO.xsl

<?xml version="1.0" encoding="UTF-8" ?>
<!--
  XSL Utility for Symphony 2
  Convert RSS feed date format to Symphony date format
  Convert RFC 2822 timestamp format to ISO date format minus the time info (Symphony CMS date format)
  RFC 2822 format: Sun, 7 Jan 2007 12:00:00 GMT
  ISO 8601 format (minus the time info): 2007-01-07
-->

<xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

	<xsl:template match="pubDate" name="format-from-rfc-to-iso">
		<xsl:param name="rfc-date" select="." />
		<xsl:param name="day-with-zero" select="format-number(substring($rfc-date,6,2),'00')" />
		<xsl:param name="month-with-zero">
			<xsl:if test="contains($rfc-date,'Jan')">01</xsl:if>
			<xsl:if test="contains($rfc-date,'Feb')">02</xsl:if>
			<xsl:if test="contains($rfc-date,'Mar')">03</xsl:if>
			<xsl:if test="contains($rfc-date,'Apr')">04</xsl:if>
			<xsl:if test="contains($rfc-date,'May')">05</xsl:if>
			<xsl:if test="contains($rfc-date,'Jun')">06</xsl:if>
			<xsl:if test="contains($rfc-date,'Jul')">07</xsl:if>
			<xsl:if test="contains($rfc-date,'Aug')">08</xsl:if>
			<xsl:if test="contains($rfc-date,'Sep')">09</xsl:if>
			<xsl:if test="contains($rfc-date,'Oct')">10</xsl:if>
			<xsl:if test="contains($rfc-date,'Nov')">11</xsl:if>
			<xsl:if test="contains($rfc-date,'Dec')">12</xsl:if>
		</xsl:param>
		<xsl:param name="year-full" select="format-number(substring(pubDate,13,4),'####')" />

		<xsl:value-of select="concat($year-full,'-',$month-with-zero,'-',$day-with-zero)" />
	</xsl:template>
</xsl:stylesheet>