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RE: question about lexical and value spaces

From: Michael Kay <mike@saxonica.com>
Date: Wed, 9 Jan 2008 16:50:21 -0000
To: "'Peter F. Patel-Schneider'" <pfps@research.bell-labs.com>, <www-xml-schema-comments@w3.org>
Message-ID: <026001c852df$b97bc4a0$2753a8c0@turtle>


There is intense debate about whether "ineffable values" (values with no
lexical representation) should be considered as being within the value space
or not. An example of such a value is a list of three zero-length strings.
In some sense the point is metaphysical, since it doesn't affect the
legality of schemas or the validity of instance documents. But it's a hot
topic within the Working Group all the same. Watch this space.

Michael Kay
http://www.saxonica.com/

> -----Original Message-----
> From: www-xml-schema-comments-request@w3.org 
> [mailto:www-xml-schema-comments-request@w3.org] On Behalf Of 
> Peter F. Patel-Schneider
> Sent: 09 January 2008 14:11
> To: www-xml-schema-comments@w3.org
> Subject: question about lexical and value spaces
> 
> 
> I have a question about the relationship between lexical and 
> value spaces in XML Schema datatypes.
> 
> In XML Schema 1.0 each value has to have at least on lexical 
> representation, as evidenced in 
> http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/#value-space
> 
> *********************
> 2.2 Value space
> 
> [Definition:]  A value space is the set of values for a given 
> datatype. Each value in the value space of a datatype is 
> denoted by one or more literals in its lexical space. 
> *********************
> 
> However I cannot find this requirement in XML Schema 1.1.
> 
> Is it true that this is a change between XML Schema 1.0 and XML Schema
> 1.1?   (By the way, I am completely in favour of this change.)
> 
> Peter F. Patel-Schneider
> Bell Labs Research
> 
Received on Wednesday, 9 January 2008 16:50:30 GMT

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