Excellent, cheers.

At 07/09/2001 11:15:32 AM, Jeni Tennison <mail@xxxxxxxxxxxxxxxx> wrote:
# ?Hi Roger,
#
# ?> I had a selection formula so;
# ?>
# ?> <xsl:template match="lg[@type='stanza' | @rend='italic']">
# ?> </xsl:template>
# ?>
# ?> <xsl:template match="lg[@type='stanza' | @rend='']">
# ?> </xsl:template>
#
# ?Really? I think most XSLT processors would raise an error with these -
# ?probably you mistyped in the mail and meant that you had:
#
# ? ?lg[@type = 'stanza' or @rend = 'italic']
# ? ?lg[@type = 'stanza' or @rend = '']
#
# ?> In my naiveity, I thought that @rend='' would be the equivalent of
# ?> testing for the non-existence of an attribute - however, not(@rend)
# ?> doesn't appear to work either. I'm using Xalan 2. what's the correct
# ?> way for testing for the non-existence of an attribute (or an element
# ?> come to that)?
#
# ?Paths like @rend result in a node set. When you convert a boolean to a
# ?node set then you get true if the node set has any nodes in, and false
# ?if it doesn't. So to test whether @type = 'stanza' or the rend
# ?attribute is not present, then use:
#
# ? ?lg[@type = 'stanza' or not(@rend)]
#
# ?> More distressingly, the first template always got ignored, not
# ?> matter what pattern I tried with the second. Why did it fail?
#
# ?Both the first and second template will match elements like:
#
# ? ?<lg type="stanza" />
#
# ?Because they both accept lg elements whose @type attribute equals
# ?'stanza'. You should try to avoid having two templates that match the
# ?same node, but if it happens then an XSLT processor will recover by
# ?choosing the later template in the stylesheet. If you want to give the
# ?first template priority, then you should add a priority attribute to
# ?it:
#
# ?<xsl:template match="lg[@type = 'stanza' or @rend = 'italic']"
# ? ? ? ? ? ? ? ?priority="2">
# ?</xsl:template>

Thats explains a lot. Thanks.


# ?Alternatively, you could change the match patterns so that they match
# ?different kinds of lg elements. For example, perhaps you meant the
# ?first to match lg elements whose @type = 'stanza' *and* @rend =
# ?'italic', while you want the second to match those lg elements whose
# ?@type = 'stanza' *and* have no @rend attribute, in which case you
# ?should use:
#
# ? ?lg[@type = 'stanza' and @rend = 'italic']
# ? ?lg[@type = 'stanza' and not(@rend)]

Doh! Of -course- that's what I meant. Thanks. Serves me right for trying to do
this -and- diy at the same time :-)

Roger



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