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Re: complexContent w/ choice minOccurs=0

From: Jeni Tennison <jeni@jenitennison.com>
Date: Fri, 17 May 2002 09:29:41 +0100
Message-ID: <11375095030.20020517092941@jenitennison.com>
To: Tom Moog <tmoog@sarvega.com>
CC: xmlschema-dev@w3.org
Hi Tom,

> Question 1: If a <choice> has no children then what does it mean to
> have a minOccurs > 0 ?

Hmm... I think that it would mean an unsatisfiable schema. A choice
entails that you have to choose an option. If there's nothing to
choose from, then the constraint is unsatisfiable. In Section 3.8.4,
it points out:

  "Nothing in the above should be understood as ruling out groups
   whose {particles} is empty: although no sequence can be ·valid· with
   respect to such a group whose {compositor} is choice..."

> Question 2 (terminology): What is the author trying to say when he
> writes "the actual value 0" instead of "the value 0".

The minOccurs attribute defaults to the value 0, so if the minOccurs
attribute is missing, then it's the same as specifying it with the
value 0. "The actual value 0" means that the value is 0 whether or not
it was actually specified within the schema document itself; I guess
"the value 0" could be read as meaning that the value is 0 and it was
actually specified in the schema document.



Jeni Tennison
Received on Friday, 17 May 2002 04:29:48 UTC

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