utypes: a proposal

[Francois Ochsenbein]

As far as I remember, it was not only the syntax -- but the
XPath expression may refer to non-unique parts of the schema,
and the same part of the schema can be designated with several
expressions. Therefore it can't be a 1 to 1 relation -- which
is what Doug requires.

Francois

>
>Hi Norman,
>
>On Thu, 30 Oct 2008, Norman Gray wrote:
>
>> How about this:
>>
>>   For each literal value defined in a data model, define as its utype
>>   that XPath which would retrieve the literal values from
>>   the 'natural' XML serialisation of the data model.
>>
>> That's all -- beginning and end of proposal.  The following illustrates how
>> this would appear.
>
>Excellent proposal! I wanted to post exactly the same message on the DM list,
>but you were the first! Francois tried to propose this syntax almost two years
>ago for the CharDM but it was rejected by the sub-group, so it never appeared
>on the general DM list. As far as I remember, at that time the argument was
>"it is a way too complex".
>
>I don't understand why not to follow this idea. Presently, UTYPEs look like
>"almost-XPath" but not exactly. The differences are: (1) "." instead of "/";
>(2) no "[]" with additional constraints; (3) no reference to a namespace (this
>seems to change with the latest Francois' proposal).
>
>Since the UTYPEs may be used outside an XML context, the only issue is how to
>deal with namespaces, I mean how to resolve them if there is no explicit link
>to a corresponding XML schema.
>
>With best regards,
> 						Igor
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