<xsl:template name="get_week_day_by_date">
    <xsl:param name="iYear" />
    <xsl:param name="iMonth" />
    <xsl:param name="iDay" />

    <xsl:variable name="y">
        <xsl:choose>
            <xsl:when test="number($iMonth) &lt; 3">
                <xsl:value-of select="$iYear - 1" />
            </xsl:when>
            <xsl:otherwise>
                <xsl:value-of select="$iYear" />
            </xsl:otherwise>
        </xsl:choose>
    </xsl:variable>
    <xsl:variable name="m">
        <xsl:choose>
            <xsl:when test="number($iMonth) &lt; 3">
                <xsl:value-of select="number($iMonth) + 12" />
            </xsl:when>
            <xsl:otherwise>
                <xsl:value-of select="number($iMonth)" />
            </xsl:otherwise>
        </xsl:choose>
    </xsl:variable>
    <xsl:variable name="d"><xsl:value-of select="number($iDay)" /></xsl:variable>
    <xsl:variable name="wd"
        select="(2 - floor($y div 100) + floor (floor ($y div 100) div 4) + floor(365.25 * $y)
        + floor(30.6001 * ($m+1)) + 1720996 + $d) mod 7"
    />
    <xsl:choose>
        <xsl:when test="$wd = 0">7</xsl:when>
        <xsl:otherwise><xsl:value-of select="$wd" /></xsl:otherwise>
    </xsl:choose>
</xsl:template>

<xsl:template name="get_month_length_by_date">
    <xsl:param name="iMonth" />
    <xsl:param name="iYear" />

    <xsl:value-of
        select="30+number($iMonth - number(boolean(number($iMonth) > 7))) mod 2
        - number(boolean(number($iMonth) = 2)) * 2
        + number(boolean(number($iMonth) = 2)) * (number(not(boolean($iYear mod 4))) * 2)"
    />
</xsl:template>