master.xml

<?xml version="1.0" encoding="UTF-8"?>
<data>
    <events>
        <event>
            <title>Recurring Exciting Event</title>
            <date>2013-01-01</date>
            <end-date>2013-12-31</end-date>
            <recurring>yes</recurring>
            <recurring-number>7</recurring-number>
            <recurring-type>days</recurring-type>
        </event>
    </events>
</data>

master.xsl

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:date="http://exslt.org/dates-and-times" extension-element-prefixes="date">

    <xsl:output method="text" indent="yes" omit-xml-declaration="yes"/>

    <xsl:template match="/">
        <xsl:apply-templates select="data/events/event"/>
    </xsl:template>

    <xsl:template match="event">
        <xsl:value-of select="date"/>
      <xsl:call-template name="date-recursion"/>
    </xsl:template>


<!-- Entering in static values, not using the XML yet, this works when you look at the result -->      
      
    <xsl:template name="date-recursion">
        <xsl:param name="repeat" select="7"/>
        <xsl:param name="count" select="$repeat"/>
        <xsl:param name="start-date" select="'2013-01-01'"/>
        <xsl:param name="end-date" select="'2013-12-31'" />
        
        <xsl:param name="date-diff">
            <xsl:value-of select="date:difference($start-date,$end-date)"/>
        </xsl:param>

        <xsl:if test="$count &lt;= translate($date-diff,'PD','')">
            <xsl:text>, </xsl:text>
            <xsl:value-of select="date:add($start-date,concat('P',$count,'D'))"/>

            <xsl:call-template name="date-recursion">
                <xsl:with-param name="count" select="$count + $repeat"/>
            </xsl:call-template>
        </xsl:if>

    </xsl:template>

</xsl:stylesheet>