utype questions

[Norman Gray]

Rob, hello.

On 2009 Jul 1, at 14:56, Rob Seaman wrote:

> Isn't the intended usage for utype something like:
>
> 	<whatisit utype="ns:target.class">whatitis</whatisit>
>
> When Doug says:
>
>> A major point of UTYPEs is to provide a simple, direct, and  
>> *unique* way to specify the field of a specific data model.
>
> Isn't this in reference to the value of the utype attribute in the  
> example above?

I think that here the utype ns:target.class is an item in a datamodel  
(ontology of measurements) which indicates what role the <whatisit>  
element is playing, and the value of this, the 'whatitis' is  
potentially drawn from a _different_ ontology or vocabulary of  
physical objects.  I agree that there's a potential issue about  
legislating for this value, but believe that the lack of legislation  
doesn't necessarily matter.

This is presuming that ns:target.class isn't one of those utypes that  
only makes sense when it's coordinated with a set of other utypes from  
the same model (the goal 1 of utypes, as I understand it).  If it  
makes sense by itself, then that's excellent, it means that it's been  
artfully repurposed here, and an application can reliably/safely  
understand this bit of XML without necessarily having heard of the  
<whatisit> element before.

Best wishes,

Norman


-- 
Norman Gray  :  http://nxg.me.uk
Dept Physics and Astronomy, University of Leicester, UK