Re: [xsl] Having Trouble With Condition For Default Nodeset Selection

[Duncan Anker <danker@xxxxxxxxxxxxx>]

On 05/07/2006, at 19:30, Michael Kay wrote:

> I think you're making the old mistake of writing @code != 'US' when  
> you mean
> not(@code = 'US').
>
> If there's no @code attribute, the first expression returns false  
> (because
> there is no code that is not equal to 'US'), while the second  
> returns true.

Thanks for the clarification, Michael, that was quite helpful.  
Intuitively, I was fairly certain there is a difference between A !=  
B and not(A=B) but I wasn't able to wrap my head around it enough to  
follow it through. I am probably thinking too much in terms of  
boolean logic where they are the same thing, and still coming to  
terms with the set theory which is so prevalent in XSLT.

Ken's solution worked for me, so happily I didn't need to do my head  
in thinking about it  :)

> Generally in XSLT, there are very few cases where A!=B is correct and
> not(A=B) is wrong.
>
> Michael Kay
> http://www.saxonica.com/
>
>
> > -----Original Message-----
> > From: Duncan Anker [mailto:danker@xxxxxxxxxxxxx]
> > Sent: 05 July 2006 00:57
> > To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> > Subject: [xsl] Having Trouble With Condition For Default
> > Nodeset Selection
> >
> > Hi Folks,
> >
> > I am trying to look up a country code in a list of supported
> > currencies, with a default to US if it is not found. I am
> > using the XSLT 1.0 idiom of
> >
> > nodeset1[condition] | nodeset2[not(condition)]
> >
> > for a mutually exclusive result, however for the life of me I
> > can't seem to find a suitable condition - I probably just
> > need a figurative whack on the side of the head to help me
> > "think different" (or should that be "differently?"). I have
> > tried several different variations of the following with no
> > luck, though I am probably just overlooking something really obvious:
> >
> > <xsl:variable name="currency"
> > select="$currency-data//currency[@code=$country-code and
> > @code != 'US']
> > | $currency-data//currency[not(@code=$country-code and @code
> > != 'US')]"
> > | />
> >
> > Nothing seems to work no matter how I arrange that - the US
> > currency is always unioned into the set. I'm sure that's the
> > wrong condition to use, and there is something relatively
> > simple I can add, but I'm just not seeing it.
> >
> > Does anyone have any suggestions, or perhaps a nerf mallet?
> >
> > Thanks in advance
> >
> > --
> > Duncan Anker
> > Server 101, Web Hosting & E-Commerce
> > http://www.server101.com