Re: [VCARDDAV] PREF interoperability

[Simon Perreault <[e-mail]>]

On 2010-11-03 16:28, Simon Perreault wrote:
> On 2010-10-12 02:42, Rohit Khare wrote:
>> * PREF reminds me of content-negotiation in HTTP. It was a
>> beautiful idea that was convoluted too far to really ever work. The
>> similarities begin with the arbitrary 0-100 scale (oops! 1-100 see?
>> and 1 > 100, don’t forget — this kind of scaling jiggery-pokery is
>> unlikely to interoperate, much less compose (concatenating records
>> from multiple sources). Where is the actual reference to a running
>> system with that much subtlety of expression?
> 
> At this late stage in the process, we need concrete and explicit 
> proposals. I can't find one in this (still interesting and valuable) 
> comment.

I'm sorry, I found your proposal in the following:

> Editorial Recommendation: By contrast, I can bet you that users care
> immensely about the *exact order* that fields were typed in. Why not
> make this ORDER, if we don’t want the original sequential occurrence
> of lines in the file to be controlling law? If anything, I’d wish we
> ruled out the use of PREF precisely because the same four characters
> exist in RFC 2426 with a completely different meaning (and it’s a
> presence/absence token to boot, not a parameter)

The order of properties is irrelevant since at least vCard 2.1.
Introducing this would mean a major break of backward compatibility.
This idea (which I proposed myself IIRC) was ruled out by the working
group in favour of an integer-valued PREF parameter.

Using the order of properties would also create other problems:

- Non-preference is going to be the most common case, but there is no
way to represent that when preference follows order.

- CardDAV would need to be heavily modified to keep properties in order.
  - There is also no way in CardDAV to make queries related to the order
of properties, whereas it is easy to construct queries including the
value of the PREF parameter.

Simon
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