Re: Avoiding boneheaded mistakes in XSLT?

On Wed, Dec 29, 2010 at 02:39:04PM +0000, Dave Pawson scripsit:
> On Wed, 29 Dec 2010 13:14:15 +0000
> David Carlisle <davidc@xxxxxxxxx> wrote:
> > On 29/12/2010 13:09, Piet van Oostrum wrote:
> > > It would be nice if processors would have a debug mode in which
> > > XPath expressions would be checked against a schema or DTD and give
> > > a warning when some 'impossible' expression is encountered.
> > > Impossible meaning something that never can give a non-empty result
> > > on valid documents. Probably just paths that are illegal according
> > > to the schema.
> > 
> > That's exactly what a schema aware xpath2 processor will do.
> 
> Even without schema awareness/context, surely the processor can
> tell when an xpath expression will result in zero match?

But a zero match is completely legitimate, isn't it?

If I'm matching on para/b, and much of my input doesn't have it, and
some of it does, I shouldn't get a warning because I'm looking for
something that isn't in this particular input file.

Or am I completely mis-understanding what you want, there?

-- Graydon