Advanced XSL Scripting

<tr>
  <td class="cellComments" colspan="4">
    <xsl:variable name="AssignHistory" select="document('AssignHistory.xml')"/>
    <xsl:variable name="week" select="Date/@NextWeek"/>
    <xsl:variable name="history-week" select="$AssignHistory/AssignmentHistory/*[name()=$week]"/>
    <xsl:choose>
      <xsl:when test="$history-week/node()">
        <!--We have history content for the specified week-->
        <xsl:variable name="NextReviewQuestion" select="$history-week/ReviewQuestion"/>
        <xsl:if test="normalize-space($NextReviewQuestion) != ''">
          <xsl:text>Question: </xsl:text>
          <xsl:value-of select="$NextReviewQuestion"/>
        </xsl:if>
        <br />
        <br />
        <br />
        <span style="font-size: 8pt;">
          <xsl:apply-templates select="$AssignHistory/AssignmentHistory/*[name()=$week]/StudentItems">
            <xsl:with-param name="MainHall" select="//Labels/MainHall"/>
            <xsl:with-param name="AuxClass1" select="//Labels/AuxClass1"/>
            <xsl:with-param name="AuxClass2" select="//Labels/AuxClass2"/>
          </xsl:apply-templates>
        </span>
      </xsl:when>
      <xsl:otherwise>
        <!--There was no history. Assume it was a special event (no meeting) so move to the subsequent week-->
        <xsl:variable name="NextReviewQuestion" select="$history-week/following-sibling::*/ReviewQuestion"/>
        <xsl:if test="normalize-space($NextReviewQuestion) != ''">
          <xsl:text>Next week is a special event. Below is the details for the week after.</xsl:text>
          <br />
          <xsl:text>Question: </xsl:text>
          <xsl:value-of select="$NextReviewQuestion"/>
        </xsl:if>
        <br />
        <br />
        <br />
        <span style="font-size: 8pt;">
          <xsl:apply-templates select="$history-week/following-sibling::*/StudentItems">
            <xsl:with-param name="MainHall" select="//Labels/MainHall"/>
            <xsl:with-param name="AuxClass1" select="//Labels/AuxClass1"/>
            <xsl:with-param name="AuxClass2" select="//Labels/AuxClass2"/>
          </xsl:apply-templates>
        </span>
      </xsl:otherwise>
    </xsl:choose>
  </td>
</tr>