You could produce the error only once by writing

count(preceding-sibling::key[. = current()] = 1)

or if you prefer:

following-sibling::key[. = current()] and not(preceding-sibling::key[. =
current()])

Michael Kay
http://www.saxonica.com/ 

> -----Original Message-----
> From: Todd Ditchendorf [mailto:itod@xxxxxxxxx] 
> Sent: 19 July 2006 22:52
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject: Re:  More XPath 1.0 Expression help
> 
> Thanks Mike and Spencer, that definitely got me going in the 
> right direction!
> 
> However, I don't think I have XSLT grouping available to me 
> in this case... let me explain.
> 
> This XPath is to be used in a Schematron <sch:asstert> test 
> attribute. I am using the XSLT ref impl of Schematron 1.5 
> running against libxslt witch is limited to XSLT 1.0 and 
> XPath 1.0. I don't think i can access exslt from the 
> schematron schema ,so exslt is out.
> 
> Also, I'm assuming that I cannot access XSLT grouping 
> mechanisms from within the schematron schema, so that, 
> unfortunately, is out too. : 
> ( Please correct me if I'm wrong there.
> 
> So here's what i've got so far:
> 
> 
> 
> 	<sch:pattern name="Report Duplicate Keys">
> 		<sch:rule context="/plist/dict/key">
> 			<sch:assert 
> test="count(../key[.=current()]) = 1">
> 					Duplicate 
> '<sch:value-of select="."/>' key exists
> 					<sch:value-of 
> select="count(../key[.=current()])"/> times.
> 					Keys should be 
> unique.</sch:assert>
> 		</sch:rule>
> 	</sch:pattern>
> 
> 
> So I have access  to the XSLT current() func but no XSLT 
> grouping features AFAIK. This rule gets the job of detecting 
> duplicate keys done... unfortunately it also raises n errors 
> for n duplicate keys rather than just one error for n 
> duplicate keys. That's certainly not a show-stopper... but it 
> would be nice to fix.
> 
> Any ideas?
> 
> The O(n^2) complexity doesn't bother me in this instance as 
> perf is not a prime concern here and the data set is very 
> small anyway.
> 
> Here's what the actual input looks like... it's an Apple plist:
> 
> <plist>
> <dict>
> <key>Key1</key>
> <value/>
> <key>Key2</key>
> <value/>
> <key>Key3</key>
> <value/>
> <key>Key1</key>
> <value/>
> </dict>
> </plist>
> 
> 
> Todd
> 
> 
> On Jul 19, 2006, at 2:22 PM, Michael Kay wrote:
> 
> Take a look at http://www.jenitennison.com/xslt/grouping
> 
> Most of the techniques for grouping are at the XSLT level, 
> but you can use the basic
> 
> key[not(. = preceding-sibling::key)]
> 
> if you don't mind O(n^2) complexity.
> 
> This detects the distinct values: leave out the not() and you 
> have an expression that detects the duplicates.
> 
> Michael Kay
> http://www.saxonica.com/
> 
> 
> -----Original Message-----
> From: Todd Ditchendorf [mailto:itod@xxxxxxxxx]
> Sent: 19 July 2006 22:18
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject:  More XPath 1.0 Expression help
> 
> 
> I need some help constructing an XPath to detect nodes 
> containing duplicate string-values. I am currently restricted 
> to XPath 1.0 syntax , so no access to distinct-values() or 
> exslt unfortunately.
> 
> I have a document like this:
> 
> <dict>
> <key>Key1</key>
> <value/>
> <key>Key2</key>
> <value/>
> <key>Key3</key>
> <value/>
> <key>Key1</key>
> <value/>
> </dict>
> 
> How do I create an XPath 1.0 expression to detect the <key> 
> elements with duplicate string-values?
> 
> 
> Thanks!
> 
> 
> Todd Ditchendorf
> Software Engineer
> itod@xxxxxxxxx