Re: [xsl] Question on Kaysian method for set intersection

[Michael Kay <mike@xxxxxxxxxxxx>]

On 28/03/2012 12:16, Hermann Stamm-Wilbrandt wrote:
> I used Kaysian method as described in this document (section 1c), sofar:
> http://www.xml.org//sites/www.xml.org/files/xslt_efficient_programming_techniques.pdf#page=3
>
>
> Now I wanted to use it similarly for nodesets from different parts of
> document.
> That does not work because /flags[1]/flag[.='A'] is not the same node
> as /flags[2]/flag[.='A'].
> Is it possible to get the flag with "A" for $int and flags for "A", "B" and
> "C" for $uni?
> If so, with keys?
The so-called Kaysian method is a way of doing identity-based node-set 
intersection and difference in XSLT 1.0, which does not offer the 
"intersect" and "except" operators.

You seem to be wanting to do equality-based intersection and difference, 
which is actually much simpler, for example

$x/ns1/flags/flag[not(. = $x/ns2/flags/flag)]

selects the flags that are in ns1 but not in ns2.

Michael Kay
Saxonica