actually that helps a lot...my problem is not with a procedural
programming past but virtually no programming past...although a
javascript course in graduate school provided practice in pseudocode..

this is something that I can use elsewhere in my
stylesheet....contributor names come in 4 different elements and
dozens upon dozens of type...

thanks again..

regards,
dana

On Mon, Jun 11, 2012 at 8:05 PM, Syd Bauman <Syd_Bauman@xxxxxxxxx> wrote:
>> don't yet understand how the empty xsl:when does it (although I've
>> used it before)...but works like a charm..
>
> Perhaps more intensive commenting will help:
>
>  <!--
>   We're going to hit this template several times in a row, once for
>   each <productidentifier>. We want to print out the ISBN13 if there
>   is one, and the ISBN10 if there is no ISBN13. So when we are
>   called for a <productidentifier>, we have to figure out whether to
>   generate output or not by looking at ourself and our siblings.
>   * if we are the ISBN13 case, print out
>   * if we are not the ISBN13 case, but one of our siblings is, then
>     don't do anything (the ISBN13 will be printed when our sibling is
>     matched by this very template)
>   * if we are not the ISBN13 case, and none of our siblings are
>     ISBN13, and we are the ISBN10, then print it out
>   * if we are not the ISBN13 case, and none of our siblings are
>     ISBN13, but we are not the ISBN10, then a warning message
>  -->
>  <xsl:template name="isbn" match="productidentifier">
>    <xsl:choose>
>      <!-- first take care of the "I am ISBN 13" case -->
>      <xsl:when test="child::b221 = '15'">
>        <controlfield tag="001">
>          <xsl:text>ISBN13 = </xsl:text>
>          <xsl:value-of select="b244"/>
>        </controlfield>
>      </xsl:when>
>      <!-- if we've gotten this far, this is not the "I am ISBN 13" case -->
>      <!-- test to see if we have a sibling that is hte ISBN 13 case;
>      if so, do nothing, as this template will do the work (above) when
>      it hits that sibling -->
>      <xsl:when test="parent::*/child::productidentifier/child::b221 =
'15'"/>
>      <!-- we've gotten this far, so there is no sibling ISBN 13;
>      so use ISBN 10, if that's what I am -->
>      <xsl:when test="child::b221 = '02'">
>        <controlfield tag="001">
>          <xsl:text>ISBN10 = </xsl:text>
>          <xsl:value-of select="b244"/>
>        </controlfield>
>      </xsl:when>
>      <xsl:otherwise>
>        <xsl:message>Danger, Will Robinson! a 'productidentifier' that is
confusing</xsl:message>
>      </xsl:otherwise>
>    </xsl:choose>
>  </xsl:template>
>



--
Dana Pearson
dbpearsonmlis.com