Re: [UCR] Action 9 and discussion of UCs

Christian de Sainte Marie wrote:
> Dave Reynolds wrote:
>>
>> "Nothing in the use case motivates the "XML data" (whatever it means) 
>> nor "XML types" requirements: their respective applications 
>> interchange data as XML documents, but that tells us nothing about how 
>> they process the data they interchange."
>>
>> Is that really true? Surely the exchange only works if the expressions 
>> within the exchanged rules which are expressions over data values are 
>> linked to the XML format in which the data is being exchanged?
>>
>> Sure the run time processing might be over some arbitrary 
>> datastructure and the translator needs to translate the data-access 
>> parts of the rules to match that datastructure. However, as far as the 
>> interchange process is concerned the rules are specified in terms of 
>> some agreed exchange data model which seem to be XML in your case 
>> (though of course it could be RDF :-)).
> 
> You are absolutely right. What we need here is, indeed, RIF being able 
> to reference the place where the vocabulary is defined (an XML schema, 
> in that case, but could be anything else); and maybe also the data 
> source, but this is another question.

It's not just the vocabulary but the semantics. For example if your 
rules are going to do tests and arithmetic on values transmitted over 
that XML then the semantics of those tests ought to be compatible with 
the corresponding XML datatypes - including all the annoying corner 
cases of NaNs, treatment of equality in floats/doubles, type promotion 
etc. If either end use different representations for the concrete types 
internally then the RIF "translators" are going to have to compensate (ha).

> My point is that I am not sure 
> that this is what the "XML data" requiremnt is about ("RIF must be able 
> to accept XML elements as data").

I think it is but then I'm more interested in the RDF equivalent and 
haven't been paying enough attention to the XML requirements.

Dave

Received on Tuesday, 19 September 2006 19:38:15 UTC