[sc34wg3] occurrence - basename fuzzy border

[Nikita Ogievetsky]

* Lars Marius Garshol
> 
> * Nikita Ogievetsky
> |
> | I do not like variants at all. There was no apparent need to put
> | them on baseNames.
> 
> Yes and no. We don't really need anything more than topics and
> associations, but topic maps are really about hitting the 80/20 spot,
> and I think variants are on the right side of that line. They are
> close, admittedly, but still on the right side, IMHO.

I would estimate that they are providing for a 0.5% out of 80%
 
> | (You may say sorting and display... well it could have been done
> | differently, i.e. through reification, etc. as Steve had mentioned)
> | .
> 
> Sure.
> 
> | However if they are there and if baseName assertion is just a
> | special case of more general occurrences assertion then why the
> | asymmetry? 
> 
> One reason is structural: base names are always inline strings,
> whereas occurrences may be external resources.

So?

> | Variants on occurrences might have been just as useful.  For example
> | they might be used to indicate different ways to access a resource
> | depending on the device context, protocol, location, etc.
> 
> I agree. The question is how often we need that, weighed against the
> cost of the change. I'd be very interested to hear from people who
> have come across this need in real life?

I agree that it is an exotic requirement but it exists.
And there are others, for example those mentioned by Geir.

> | As I had mentioned in Baltimore, variants provide for the only
> | difference between occurrence and baseName elements.
> | Especially now when we had introduced instanceOf child elements on
> | baseNames.
> 
> There's still the inline/external difference. 
>  
> | Allowing variants on occurrences will make content model more
> | uniform and it will still be backward compatible.
> 
> Uniformity of content models is a goal, admittedly, but I am not sure
> that occurrence variants will be using the same element type and the
> same information item type. We'd either generalize the variant concept
> further, or distinguish occurrence variants from name variants.

I agree: it is not that trivial.
  

--Nikita

Nikita Ogievetsky, nogievet@cogx.com;
Cogitech Inc.        http://www.cogx.com   
Topic Maps Tutorials and Consulting. 
phone:  1 (917) 406 - 8734