relProperty Re: [uf-rest] Roy Fielding on WebDAV and PROPs

[Dr.Ernie Prabhakar]

Hi Breton,

On May 5, 2006, at 6:01 PM, Breton Slivka wrote:
> On May 5, 2006, at 5:46 PM, Dr. Ernie Prabhakar wrote:
>> http://microformats.org/wiki/rest/property#relProperty
>>>
>>> Are you talking about listing each property seperately in their  
>>> own link statement? Or a link to a file describing the URI schema  
>>> in use for the properties of that page?
>>
>> The former, I think; otherwise, it becomes difficult to "identify  
>> each individually update-able resource with its own URI."   
>> Clarified at: http://microformats.org/wiki/rest/property#
>>
>
> The reason I ask is this then sounds suspiciously like the meta tag  
> with some server updating code tacked on.

Ah, here's the difference.  "relProperty"  is a *pointer* to a value,  
which lives in a different resource.  The meta tag is an "immediate"  
variable (if I have my terms right): the value is embedded within the  
document, and thus can't be updated independently.  This harkens back  
to our extrinsic vs. intrinsic metadata issue.

I've tried to make that clearer at: http://microformats.org/wiki/rest/ 
property#relProperty

>> I'm not clear why ";" creates hierarchy problems?  My gut-level  
>> interpretation would be:
>>
>> 	;prop1;prop2 are chained properties
>> 	;prop1/subprop1 is a "hierarchical" property
>>
>> That is, we just reuse the existing HTML hierarchy separator.   
>> What would be the problem with that?
>
> Ambiguity
>
> http://example.org/test/books;citation/author=Breton;title=example
>
> is author a subproperty of citation, or a  subdirectory of books?  
> Is title a child of citation, or a child of books?

I think we may be talking past each other. I fully agree that just  
saying "; is a separator" is ambiguous.  That is *why* this is an  
open issue -- we need to fully specify exactly how those corner cases  
need to be handled.  To be sure, that is a lot of work -- but  
(assuming we accept the need for hierarchical properties) *that* work  
has to be done, regardless of the encoding used.

Rather than argue in the abstract, let me suggest some _possible_  
rules for how chaining and hierarchies could work:

http://microformats.org/wiki/rest/property#.3Bproperty

I'm not happy with them, but its just a starting point -- alternate  
suggestions are welcome! Again, if you think about this as replacing  
WebDAV, not "meta" tags, the usage scenarios might make more sense.   
Any thoughts about how to make that distinction clearer would be  
greatly appreciated.

Thanks for the feedback!

-- Ernie P.