Re: [xsl] Interpretaion of grouping for-each

[David Carlisle <davidc@xxxxxxxxx>]

> What does count() =1 represent (got a bit confused about jeni's
> explanation)

No, that's the wrong way round. The usual pattern is that I give the
confusing (or at least terse) explanation and Jeni explains it.

> count(. | .....) =1

XSLT 1 does not have a test for node identity, you can use = to test if
one node has the same value as another but not whether it actually is
the same node.

You have an expression ...... (actually viewentry{key('ve-by-firstocc', 
substring(entrydata[3]/text,1,1))[1]] ) that returns a node, and you
want to know if that node is the current node, not just if it has the
same character data, there are two methods to test that in xslt 1 (in
Xpath 2 you could just use

. is viewentry{key('ve-by-firstocc', substring(entrydata[3]/text,1,1))[1]] )


as the is operator tests node identity.

however in xslt 1 you use the set union method:

(. | .....) 

is a set of nodes being the union of the current node (.) and the other
one (....) so either there is one node in this set (if . and ..... are
the same) or 2 nodes (if they are different) so testing count()=1
will determine this identity.

The other method (which is the one I tend to use as it's slightly
clearer I think) is to test

generate-id(.) = generate-id(.....) 

as generate-id will return an id string taht is unique to each node, so
testing these strings will test identity.

note in the above "." means "." bit "...." is a meta placeholder for the
expression of interest (key('ve-by-firstocc',
substring(entrydata[3]/text,1,1))[1]]" in your case)


  Just to be clear, am i right in saying that "viewentry{key('ve-by-firstocc', 
  substring(entrydata[3]/text,1,1))[1]]" selects the first of each group of 
  viewentries with the same key (including groups which only have one 
  viewentry in it)?

Yes.

David

-- 
http://www.dcarlisle.demon.co.uk/matthew

________________________________________________________________________
This e-mail has been scanned for all viruses by Star Internet. The
service is powered by MessageLabs. For more information on a proactive
anti-virus service working around the clock, around the globe, visit:
http://www.star.net.uk
________________________________________________________________________

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list