Something like RDF and Structure for TAs

[stephen.green@systml.co.uk]

Greetings TAG TC

I was just reading a posting on XML Dev and a link posted was to
W3C's GRDDL spec which has this introduction which looks very
similar to the way I've personally been trying TAs in recent work:

http://www.w3.org/2004/01/rdxh/spec#intro

It does seem to relate to my own thinking about structuring a TA.

In short I'd see an idealized TA as the equivalent of what GRDDL
notes as an RDF triple, namely:

Subject (read IUT) + predicate (read TA in predicate form) + object
(read part of the predicate which is outside of the mere logic)

So for example if I have a spec which reads
"The issue date is mandatory and must be of the format DDMMYYYY"
I can break that down as two TAs:

common to both:
* Spec Ref: http://www.mycompany.com/spec#101
* Subject (IUT): Issue Date

TA Id: #101.01:
Predicate: Is mandatory (or expressed with XML Schema language, minOccurs = 1)
Object: cardinality

TA Id: #101.02
Predicate: Is DDMMYYYY (need an attribute, as Jacques says, for whatever
    expression language DDMMYYYY is)
Object: format

Then these TAs can easily be expressed I would think using RDF
(borrowing from the W3C example and adapting it to a TA model but I'm
not sure whether Dublin Core has anything like a TA's IUT or whether
FOAF has anything useful, mind, but you get the idea) to give something
like:

<rdf:RDF
     xmlns:ta="http://some-tag-url.org/...";
     xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
     xmlns:core="http://purl.org/...";>

   <rdf:Description rdf:about=
"http://www.mycompany.com/spec/ta-101.01/6b050dcf-7ab1-456d-9e1b-c3c41c18eed2";>
     <core:IUT>Issue Date</core:IUT>
     <tag:has>
       <tag:Cardinality rdf:about=
    
"http://www.mycompany.com/date/syntax/xsd/33b3c323-77c2-417c-a5b4-af7e6a111cc9";>
         <tag:expression>minOccurs='1'</tag:expression>
       </tag:Cardinality>
     </tag:has>
<rdf:Description rdf:about=
"http://www.mycompany.com/spec/ta-101.02/6b050dcf-7ab1-456d-9e1b-c3c41c18eed2";>
     <core:IUT>Issue Date</core:IUT>
     <tag:has>
       <tag:Format rdf:about=
    
"http://www.mycompany.com/date/syntax/???/33b3c323-77c2-417c-a5b4-af7e6a111cc9";>
         <tag:expression>Is DDMMYYYY</tag:expression>
       </tag:Format>
     </tag:has>

   </rdf:Description>
</rdf:RDF>

No idea if this is proper RDF but it gives an idea of what I'm thinking about.
I'm not sure I'd choose RDF to express a TA but the tuple approach seems
to me to be quite suitable for TAs and seems to back the concept of splitting
a TA formally into 'IUT + predicate...' and perhaps I think '...+ Subject'.
So I'm suggesting, I suppose (based on my own experiments for a recent
project) splitting the predicate (whether it is called predicate or outcome)
into a logical predicate part and an object, assuming the IUT is the subject.

Maybe people will want to use RDF so this might help facilitate doing so.

Best regards

-- 
Stephen Green

Partner
SystML, http://www.systml.co.uk
Tel: +44 (0) 117 9541606

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