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Re: XSV fails on negative regexp (eg mimetype of MPEG7)

From: Henry S. Thompson <ht@inf.ed.ac.uk>
Date: Thu, 13 Sep 2007 11:20:37 +0100
To: Heiko Studt <studt@fmi.uni-passau.de>
Cc: xmlschema-dev@w3.org
Message-ID: <f5bfy1i9896.fsf@hildegard.inf.ed.ac.uk>

Hash: SHA1

Heiko Studt writes:

> XSV seems to fail on xsd-allowed 'negated' regular expressions in
> patterns. This breaks the support of
> MPEG7:mimetype. (urn:mpeg:mpeg7:schema:2004) Allthough XSV documents
> lacks functionality in some parts of RegExp, this lack is not
> documented on its project page.

Well, I admit it's pretty obscure, but the project page [1] does say,
in the list of implemented features "pattern (partially)".  The truth
is that XSV uses Python's native regexps if it thinks that will give
the right answer, otherwise just falls back to saying "yes".  Python
regexps don't support subtraction, so the presence of that in your
pattern provokes the fallback.

I'm afraid I can't comment on whether your two regexps are
equivalent. . .


[1] http://www.ltg.ed.ac.uk/~ht/xsv-status.html
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 Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
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Received on Thursday, 13 September 2007 10:20:49 UTC

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