W3C home > Mailing lists > Public > public-qt-comments@w3.org > November 2003

[XQuery] 2.6.3 Full Axis Feature

From: David Carlisle <davidc@nag.co.uk>
Date: Tue, 18 Nov 2003 15:38:27 GMT
Message-Id: <200311181538.PAA18335@penguin.nag.co.uk>
To: public-qt-comments@w3.org


What is the rationale for the full axis feature?

Having these things optional greatly harms interoperability between
Xquery systems and between Xquery and Xpath.

It would be understandable if it were (say) all the reverse axes that
were optional as there are issues supporting those axes in a streaming
manner, but since parent:: and << are both non-optional these axes can
be supported by an entirely syntactic re-write. Forcing the users to do
that is a pain, and one would assume that it is much easier for a system
to spot and optimise a specific syntax such as following-sibling::foo
than the equivalent expression
let $here := . return ../foo[$here << .]

I would strongly urge that this feature be dropped and that support for
the axes be mandatory.


David

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Received on Tuesday, 18 November 2003 10:42:32 UTC

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