Re: [xsl] Q: Kaysian set difference in pure XPath statement

[Michael Kay <mike@xxxxxxxxxxxx>]

On 24/03/2011 20:33, Hermann Stamm-Wilbrandt wrote:
> Hello,
>
> I saw a question on what "//*/*" means.
> The answer is simple, all nodes beside the root element node.
>
> This can be easily seen by this XPath expression:
> $ echo "<a><b><c/></b><b><c/><c/></b></a>" | xpath++ "count(//*)-count
> (//*/*)" -
> 1
> $
>
> Now I wanted to use Kaysian set difference method to output the
> node in "//*" which is not in "//*/*", see 1a on this page:
> http://www.xml.org//sites/www.xml.org/files/xslt_efficient_programming_techniques.pdf#page=3
>
> But here two nodesets ($ns1, $ns2) are determined first before determining
> the set (asymmetric) difference as "$ns1[count(.|$ns2)!=count($ns2)]".
>
> Is it possible to have that as pure XPath statement?

You're using "pure XPath" to mean "XPath 1.0", which seems a bit odd to 
my ears....
> The problem is to jump out of the scope of "//*[. ...]".

What (apart from efficiency) is wrong with

//*[count(. | //*/*) != count(//*/*)]

(Though it's not clear why you can't just write /*)

Michael Kay
Saxonica
> This does not work correctly:
> $ echo "<a><b><c/></b><b><c/><c/></b></a>" | xpath++ "//*[count(.|
> ancestor-or-self::*//*/*)!=count(ancestor-or-self::*//*/*)]" -
>
> -------------------------------------------------------------------------------
> <a><b><c/></b><b><c/><c/></b></a>
> -------------------------------------------------------------------------------
> <b><c/></b>
> -------------------------------------------------------------------------------
> <b><c/><c/></b>
> $
>
>
> What is the correct XPath statement for "//* minus //*/*"?
>
>
> [1]
> https://www.ibm.com/developerworks/forums/thread.jspa?messageID=14511881#145
> 11881
>
>
> Mit besten Gruessen / Best wishes,
>
> Hermann Stamm-Wilbrandt
> Developer, XML Compiler, L3
> Fixpack team lead
> WebSphere DataPower SOA Appliances
> https://www.ibm.com/developerworks/mydeveloperworks/blogs/HermannSW/
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