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Re: Why not reinvent the wheel?
- From: Joe English <firstname.lastname@example.org>
- To: email@example.com
- Date: Sun, 25 Feb 2001 09:31:57 -0800
Jonathan Robie wrote:
> Joe English wrote:
> >I wouldn't go that far either; the structure of XQuery does look
> >to me like it's more amenable to optimization than XSLT.
> >But the '..' axis is definitely problematic.
> Now the question - if a user chooses to write recursive functions to do
> this sort of thing, does that user have the right to expect that we will
> optimize such queries well?
I think that '..' may turn out to be one of those features
that you have to pay for even if you don't use it.
Since an XQuery engine _might_ need to evaluate '..',
it rules out many implementation strategies that would be
more space-efficient than those used by conventional XSLT
It will be interesting to see what XQuery implementors
come up with though. I have a hard time envisioning a
space-efficient query evaluation framework which also
supports '..', but that's no doubt due to a lack of
imagination on my part. (OTOH, I can think of several
that don't or can't support '..'.)
I also notice that none of the example queries in the WD,
and only one in the "Use Cases" document, require '..'.
Is this feature really essential for XQuery?