XSLT Cookbook

Determining Secular and Religious Holidays

Problem

You would like to know if a given date is a holiday.

Solution

The first type of holiday includes those that fall on the same day every year. For example, a function to determine the absolute day of American Independence for any year is simply:

<xsl:template name="date:independence-day">
     <xsl:param name="year"/>
     <xsl:call-template name="date:date-to-absolute-day">
          <xsl:with-param name="month" select="7"/>
          <xsl:with-param name="day" select="4"/>
          <xsl:with-param name="year" select="$year"/>
     </xsl:call-template>
</xsl:template>

The second type of holiday falls on the same day of the week relative to the start or end of a month. You can compute those days with the help of the following utility, which wraps the k-day-on-or-before-abs-day template contained in Recipe 3.8.

<xsl:template name="date:n-th-k-day"> <!-- The n'th occurance of k in the given month --> <!-- Postive n counts from beginning of month; negative from end. --> <xsl:param name="n"/> <!-- k = the day of the week (0 = Sun) --> <xsl:param name="k"/> <xsl:param name="month"/> <xsl:param name="year"/> <xsl:choose> <xsl:when test="$n > 0"> <xsl:variable name="k-day-on-or-before"> <xsl:variable name="abs-day"> <xsl:call-template name="date:date-to-absolute-day"> <xsl:with-param name="month" select="$month"/> <xsl:with-param name="day" select="7"/> <xsl:with-param name="year" select="$year"/> </xsl:call-template> </xsl:variable> <xsl:call-template name="date:k-day-on-or-before-abs-day"> ...