[om] OM Floats (XML Representation)

[Professor James Davenport]

On Mon, 8 Dec 2003, David Carlisle wrote:
> I'm not sure xsd is as broken as was claimed. The ordering and
> inequality rules in schema relate to the ordering and inequality testing
> done by the schema validator, they don't impose constraints on the
> application.
Roughly speaking, I agree, but we should always remember, and document, 
the above point.
> There is only one NaN possible in a schema input as the only allowed
> syntax is "NaN" there are no operations in schema that could generate
> anything else. Given the semantics of schema validation testing, if NaN
> was not equal to NaN, then if a schema constrained an element to only
> have NaN then an XML file would never validate as an instance of that
> schema; as even if it had NaN in that element, it would be not equal.
> So all xsd is saying by NaN=NaN is that if a schema specifies that an
> element must, or can, have NaN, then an instance that has NaN is
> valid. This seems reasonable to me.
Not quite: there's only thing NAMED NaN. I can create many other NaNs by 
<OMF hex="..."/>. The schema won't know, but an application will.
James
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