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p:value-available not as useful as I'd like. . .

From: Henry S. Thompson <ht@inf.ed.ac.uk>
Date: Thu, 26 Nov 2009 17:32:15 +0000
To: xproc-dev@w3.org
Cc: Michael Kay <mike@saxonica.com>
Message-ID: <f5b4oohfazk.fsf@hildegard.inf.ed.ac.uk>
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The following doesn't work:

  <p:with-option name="foo"
                 select="if (p:value-available('bar') then $bar else xyzzy"/>

because the semantics of if only protect you against _dynamic_ errors
in the branch not taken, and the fact that bar isn't a know (XPath2)
variable is a _static_ error. . .

Wrapping two copies of the whole surrounding step in a p:choose/p:when
seems awfully heavyweight. . .

Any ideas for a workaround (I'm _not_ suggesting a change to the
spec. at this late stage :-)?

ht
- -- 
       Henry S. Thompson, School of Informatics, University of Edinburgh
                         Half-time member of W3C Team
      10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440
                Fax: (44) 131 651-1426, e-mail: ht@inf.ed.ac.uk
                       URL: http://www.ltg.ed.ac.uk/~ht/
[mail really from me _always_ has this .sig -- mail without it is forged spam]
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Received on Thursday, 26 November 2009 17:33:06 GMT

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