Re: Last tango in Paris

[Nigel S. <nig...@us...>]

Peter brought this bug up a while back, but we'd forgotten about it.  It has
been fixed now.  The brief story is that double predicates like
/*[last()][@Attr='X'] will now work.  If you want more background then you
can read on some of Peter and my discussion from this evening...

I think it is unlikely that this bug affects you.  I think most XPath users
only use one [] not two or more [][], but thought I should post to the list
just in case it does.

:o)

Nigel

> On Thursday 30 May 2002 20:41, Nigel Swinson wrote:
> >
> > > Also, it looks like the double predicate problem (my 'last tango
> > > in Paris' example) is still outstanding - is that correct?
> >
> > I had to go and research this but I what I found was going to
> > http://www.zvon.org:9001/saxon/cgi-bin/XLab/XML/extras.html?stylesh
> >eetFile=X SLT/xpath.xslt (Link doesn't seem to be working right just
> > now) that //*[last()] could return more than one node, so it seemed
> > that we were implementing last() right.
> >
> > There does however seem to be a second issue todo with
> > /nodetest[][] double predicates, which DOES NOT seem to be working.
> >  I don't know if it's meant to though.  Is it?  If it is then it
> > seems we still have a bug...
> >
> > Can you confirm?
>
> yes, these are 2 two different things. The problem is not with last
> but with >1 predicates. Look at say the company structure xml in the
> useCases testbench. If you do //employee[last()] it will fetch the
> last employee node in each parent (dept), 5 of them in this case,
> which is correct. If you do //employee[@gender='m'], it will fetch
> all the male employees. But if you try and combine the 2, i.e. a
> 2-stage process: fetch the male employees and then give me the last
> one //employee[@gender='m'][last()] it brings an error that it can't
> find a gender function.
> The example in the xpath spec is para[@type="warning"][5]
> In my tango example, you can fetch all the tangos in Paris, and all
> the last tangos, but not the two together.
>
> These positional ones are not too difficult to work around, as you can
> simply read all the first predicate into an array and then use php to
> fish out the one you want, but at least in principle, you can have
> any predicate and any number of predicates, tho in practice I doubt
> whether anyone would have much use for this.
>
> I don't think this is a bug btw, I don't think it was ever coded :-)
>