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Re: Re: Re: An issue with XPath 2.0 sequences (Was Re: RE: Muenchian method, and keys 'n stuff)
- From: naha at ai dot mit dot edu
- To: xsl-list at lists dot mulberrytech dot com, Dimitre Novatchev <dnovatchev at yahoo dot com>
- Date: Fri, 01 Feb 2002 11:28:06 -0500 (EST)
- Subject: Re: [xsl] Re: Re: An issue with XPath 2.0 sequences (Was Re: RE: Muenchian method, and keys 'n stuff)
- References: <20020201095118.86989.qmail@web14504.mail.yahoo.com>
- Reply-to: xsl-list at lists dot mulberrytech dot com
Quoting Dimitre Novatchev <dnovatchev@yahoo.com>:
> > > Nevertheless, I'm reasonably comfortable with it.
> >
> > I think the place where it breaks down most spectacularly is when it
> > is combined with the apparent desire to model SQL NUL values as ()
> > using a list, even an empty one, as a value does not really combine
> > with the non nested list model, which means that these "NUL" values
> > vanish at interesting times and lead to strange anomalies in
> > accumulation functions like sum() and the loss of the useful
> lisp-like
> > non-empty-node-set = true coercion that was in Xpath 1 but only
> works
> > in Xpath 2 "most of the time".
> >
> > David
>
> Also as Jeni pointed out the weird case of sequences changing their
> cardinality when mapped by a function that may return the null
> sequence...
That's very dangerous. It means that if one were doing several different
mapping operations from the same sequence the results could might be
incorrectly aligned.
I can't fathom how anyone could consider that as acceptable behavior.
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