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Re: Sometimes an empty value means "use the default value" and sometimes it doesn't ... right?

From: G. Ken Holman <gkholman@CraneSoftwrights.com>
Date: Thu, 23 Aug 2012 16:29:40 -0400
Message-Id: <>
To: "xmlschema-dev@w3.org" <xmlschema-dev@w3.org>
At 2012-08-23 19:32 +0000, Costello, Roger L. wrote:
>Sorry, I was not clear in my message.
>I was not asking a question about semantics or meaning.
>I was asking a question about the behavior of XML Schema validators.
>Hopefully this question will be clearer:
>     The XML Schema validator determines the
>     value of the empty Altitude element
>      to be the default, 100.
>     The XML Schema validator determines the
>     value of the empty Title element
>      to not be the default; instead the value
>     is the empty string.

I apologize for not recognizing your question.  The specification 
talks to your point directly:

   Note: The provision of defaults for elements goes beyond what
   is possible in XML 1.0 DTDs, and does not exactly correspond
   to defaults for attributes. In particular, an element with a
   non-empty {value constraint} whose simple type definition
   includes the empty string in its lexical space will
   nonetheless never receive that value, because the {value
   constraint} will override it.

I hope this helps.

. . . . . . . .  Ken

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Received on Thursday, 23 August 2012 20:30:12 UTC

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