[xsl] nested grouping problem

[Terry Ofner <tdofner@xxxxxxxxx>]

I have the following incoming xml:

<summary>
  <codeSum main="14" exp="A">(14) Writing:</codeSum>
  <codeSum main="14" exp="A">(14) Writing:</codeSum>
  <codeSum main="14" exp="C">(14) Writing:</codeSum>
  <codeSum main="14" exp="C">(14) Writing:</codeSum>
  <codeSum main="14" exp="C">(14) Writing:</codeSum>
  <codeSum main="14" exp="C">(14) Writing:</codeSum>
  <codeSum main="14" exp="D">(14) Writing:</codeSum>
  <codeSum main="14" exp="D">(14) Writing:</codeSum>
  <codeSum main="14" exp="D">(14) Writing:</codeSum>
  <codeSum main="14" exp="D">(14) Writing:</codeSum>
  <codeSum main="14" exp="E">(14) Writing:</codeSum>
  <codeSum main="14" exp="E">(14) Writing:</codeSum>
  <codeSum main="17" exp="A">(17) Expository:</codeSum>
  <codeSum main="17" exp="A">(17) Expository:</codeSum>
  <codeSum main="17" exp="A">(17) Expository:</codeSum>
  <codeSum main="19" exp="A">(19) Conventions:</codeSum>
  <codeSum main="19" exp="A">(19) Conventions:</codeSum>
  <codeSum main="22" exp="A">(22) Research:</codeSum>
  <codeSum main="22" exp="A">(22) Research:</codeSum>
  <codeSum main="22" exp="A">(22) Research:</codeSum>
  <codeSum main="22" exp="A">(22) Research:</codeSum>
</summary>

I am processing this with the following nested grouping template:

    <xsl:template match="summary">
        <summary><textBold>Areas:</textBold><xsl:for-each-group
select="codeSum" group-by="@main">
            <xsl:value-of select="."/><xsl:text> </xsl:text>
            <xsl:for-each-group select="current-group()" group-by="@exp">
                <xsl:choose>
                <xsl:when test="position()!=last()">
                    <xsl:value-of select="current-grouping-key()"/><xsl:text>,
</xsl:text>
                </xsl:when>
                <xsl:otherwise>
                    <xsl:value-of select="current-grouping-key()"/><xsl:text>
</xsl:text>
                </xsl:otherwise>
            </xsl:choose>
            </xsl:for-each-group>
        </xsl:for-each-group>
            </summary>
    </xsl:template>

with this result:

<summary><textBold>Areas:</textBold>	(14) Writing: A, C, D, E  (17)
Expository: A  (19) Conventions: A  (22) Research: A  </summary>

I would like to add a semicolon after the last letter (@exp) listed after each
area except for the last area in the list:

<summary><textBold>Areas:</textBold>	(14) Writing: A, C, D, E; (17)
Expository: A; (19) Conventions: A; (22) Research: A  </summary>

Is this possible inside one template? I have always grouped from the outside
in, so to speak. In this case it seems that I would need to first group the
@main[@exp], then group @main.

Otherwise I will need to leave some kind of element or attribute and take
another pass through the summary to add the semicolons. Or perhaps this is a
candidate for named template call, which is an approach that I am still fuzzy
on.

Any help would be most appreciated.

Terry