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> -----Original Message-----
> From: Jonathan Robie [mailto:jonathan.robie@softwareag.com]
> Sent: Wednesday, December 26, 2001 5:27 PM
> To: Champion, Mike; xml-dev@lists.xml.org
> Subject: RE: [xml-dev] W3C's five new XQuery/Xpath2 working drafts -
> Still missing Updates
>
> [ I am attempting to be on vacation, so I may not be very
> involved until January ]
Gee, I hang out on XML-DEV for fun, doesn't everyone :~)
>
> If you don't have strong typing, then you have programming
> errors that could have been caught by the type system. That costs people
money.
Ahhh ... I see the argument now. But this assumes not only a strongly-typed
programming language (and the last I checked, a very substantial percentage
of Web programming is done in Javascript, Perl, Python, etc.), but also a
schema-centric conception of the role of XML in web software. The "schema"
might be an RDBMS DDL description of tables, class definitions in C++ or
Java, or one of the XML schema languages, but in any event the only way to
catch programming errors with type systems is to put "types" at the very
core of a software architecture. That is one (good, and well-established)
way of doing it, but not by any means the only, or even the dominant (AFAIK)
way of doing it.
As the "T-word" thread here a few months ago
http://lists.xml.org/archives/xml-dev/200108/msg01042.html indicated, "type"
is a bit of a dirty word in some perfectly respectable circles. I am
struggling with the concepts and terminology here (I took a stab at this in
my post http://lists.xml.org/archives/xml-dev/200112/msg00356.html and
didn't get much followup). The various distinctions among classes, types,
and domains make my head hurt, and I don't claim to have any deep insights.
Nevertheless, there is an alternative conception of the role of XML in
software development that puts well-formed but informally-described XML
documents or messages deep in the architecture rather than treating XML as a
serialization syntax for objects. In this approach, XPath and XSLT can be
seen simply as convenient ways of adding or extracting information from
chunks of XML. I see that XPath 2.0 now supports FLWR expressions, and hence
joins, the lack of which was the major limitation of XPath 1.0 for anything
I ever tried to do. I'd be inclined to say that XPath 2.0 is enough to
"declare victory" so that the W3C can focus on some sort of XML update
syntax, and then XQuery as currently defined.
I'd be very interested in a reality check -- Am I the only XML developer
still living in the loosely-typed or non-typed Dark Ages? Does anyone else
see XPath 2.0 as meeting the most pressing real-world business requirements
that the XQuery folks have been working on? What percentage of real-world
XML programming errors can caught by the XQuery type system?
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