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Follow-up question wrt the previous post

From: Henry S. Thompson <ht@inf.ed.ac.uk>
Date: Thu, 14 May 2009 13:01:58 +0100
To: xproc-dev@w3.org
Message-ID: <f5b8wkzgafd.fsf@hildegard.inf.ed.ac.uk>
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So, if I want to detect and handle specially the case where an
optional option has not been specificed, how can I do so?

Using p:try seems awfully heavyweight.

In XSLT, I can distinguish between the empty string and the empty node
set, so we see the common idiom

 <xsl:param name="foo" select="xyzzy"/>

But since XProc options are always string-valued, there's no obvious
default which can be reliably distinguished from a supplied value.

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, 14 May 2009 12:02:36 GMT

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