Re: [xsl] possible value-of return values

[tcn@xxxxxxxxxxxxx (Trevor Nash)]

On Mon, 30 Jul 2001 14:38:52 -0400, you wrote:

>Hello,
>
>Given the following XML document:
><root>
><user name="Alex" password="Elephant" color=""/>
><user name="Reuter" password="Rhino"/>
></root>
>I was wondering if anyone knew the distinction in return values between:
><xsl:value-of select="/root/user[@name='Alex']/@color"/>
>And
><xsl:value-of select="/root/user[@name='Reuter']/@color"/>
>
>
>My guess is they would both be null, but I need to execute logic which
>hinges on whether the attribute exists and has a null value OR whether it
>exists at all.
>
Not 'null' but an empty string.  Both are empty strings but for
different reasons: in the first case you are getting a node set
containing the attribute node, which when converted to a string gives
the value of the attribute, in the second you are getting an empty
node set which when converted to a string gives you "".  But when
converted to a boolean a non-empty node-set gives you true, and an
empty one false.  So:

<xsl:if test="/root/user[@name='Alex']/@color">
    This is true 
</xsl:if>
<xsl:if test="/root/user[@name='Reuter']/@color">
    This is false
</xsl:if>
>Anything you got would be great.
>
>Thanks,
>
>	Alex
>
Regards,
Trevor Nash
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