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On Mon, 8 Nov 2004 08:26:29 -0500, Roger L. Costello <costello@mitre.org> wrote:
>
> Hi Folks,
>
> From my examinations, it would appear that XQuery is a superset of XSLT. I
> wonder about the future of XSLT?
I believe David Carlisle has it right: XSLT2 and XQuery are
functionally very similar. (Michael Kay's chapter in XQUERY FROM THE
EXPERTS compares and contrasts them very clearly).
That means it comes down to essentially a matter of style when
choosing to use or support one vs the other. Some of this is just a
matter of whether one prefers to work in XML syntax (XSLT) or
something more like a programming language syntax (XQuery). The
biggest difference is whether one is comfortable applying the
recursive template matching style encouraged by XSLT or the more
conventional programming style of XQuery.
In my experience working with developers and users, this is the
biggie: There is a certain hard core of SGML/XML people who just
'grok' the XSLT development style and can use if to great advantage.
But there are a lot of people (and I count myself among them, to my
shame) that just can't get anything non-trivial done in XSLT without
an example to work from and a reference manual in hand. Many of those
same people can grok the basics of XQuery pretty quickly ("oh, it's a
lot like SQL except ....").
My rough estimate from talking to XML users (as opposed to geeks) over
the years is that SQL/XQuery grokkers outnumber XSLT grokkers by
something like 10:1. Does that mean that anyone -- W3C, the big
companies, whoever -- intends to deprecate XSLT? Definitely not,
because there is no central authority in W3C (or Microsoft/IBM/Oracle,
AFAIK) who knows or cares enough about this issue to have made such a
decision, especially considering that different constituencies within
them have different opinions. Everyone is trading off the needs of
their users, the capacities of their developers, and the availability
of alternatives, and these calculations give different results over
time. For example, SQL-XML is starting to get some reality behind it,
and that might well tilt some thinking toward a strategy of "XSLT for
the people who grok it, SQL-XML for people who don't." I don't know.
Another factor is likely to be whether the XQuery/XSLT2 specs become
Recommendations in short order. I think patience is wearing thin;
even those who might have planned 5 years ago for XQuery to replace
XSLT as their preferred solution are likely to reconsider if the spec
doesn't start moving more rapidly toward completion and real industry
acceptance. [Obligatory disclaimer: I'm only reading tea leaves
here, I don't have any inside information about this from anyone]
Anyway, I would like hear from people who have strong feelings about
whether XSLT meets their needs and XQuery doesn't or vice versa,
whether SQL-XML will eventually eat XQuery's lunch in database
scenarios, and what people plan do with XQuery *besides" use it as a
database query language.
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