Re: XQuery -- Reinventing the Wheel?

[Joe English <jenglish@flightlab.com>]

Evan Lenz wrote:
>
> After reviewing the XQuery spec, I'm concluding that the overlap between
> XQuery and XSLT is far too great for the W3C to reasonably recommend them
> both as separate languages.
> [...]
> Simplistically,
>
> XQuery = XSLT - templateRules - nonAbbreviatedXPathAxes

My first impression was that the stuff left *out* of XQuery
might make it more amenable to optimization than XSLT,
particularly regarding space requirements.  However,
the XQuery WD includes the 'parent' axis, which
(in combination with BEFORE, AFTER, and recursive functions)
makes it possible to express all the other XPath axes,
so it ends up being just as difficult to optimize XQuery
for space as it is to optimize XSLT.

My second impression is that the spec is not fully cooked yet.
There are a *lot* of ambiguities and ill-defined features.

That said, there are a few good ideas in XQuery which I
hope will make their way into XSLT.  (The most important
feature -- constructed result trees as first-class citizens --
is already in XSLT 1.1, and others like existential and universal
quantification are on the list.)


--Joe English

  jenglish@flightlab.com