In XSLT 1.0 you have 4 datatypes: number, boolean, string and nodeset.

The "most-null or nothingness" which you can have for these is
0, false, "" (empty string) or empty nodeset (such as is returned by /..)
respectively and so these values are the choices to which you are limited
to when deciding what you want to return to signify a "NULL" value aside
from returning a special sentinel value, e.g. a string such as "(NULL)".

Hope this helps.


At 02:37 PM 26/07/2007 +0000, you wrote:
>HI, guru
>Do you know how to assing a NULL to variable in XSL1.0?  Thank you.
>
>My problem is I want write a code as follows, but I do not know how to set 
>a NULL value at the following "otherwise" case:
>
><xsl:variable name="myvar">
>   <xsl:choose>
>     <xsl:when test="conditon a">
>          <xsl:value-of selcet="xxx"/>
>     </xsl:when>
>     <xsl:when test="conditon b">
>          <xsl:value-of selcet="xxx"/>
>     </xsl:when>
>     <xsl:otherwise>
><!--       WANT TO return a NULL value here!!!!!  But It return a "" not 
>NULL -->
>     </xsl:otherwise>
>   </xsl:choose>
></xsl:variable>
>
><xsl:if test="$myvar">
> .....
></xsl:if>

Justin Johansson

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