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Re: PROPOSAL to address RDFa Profiles - ISSUE-73 and ISSUE-78

From: Ivan Herman <ivan@w3.org>
Date: Thu, 10 Feb 2011 09:58:39 +0100
Cc: W3C RDFa WG <public-rdfa-wg@w3.org>
Message-Id: <7E300595-9FF6-4AF3-B14C-2962491BDE6D@w3.org>
To: Manu Sporny <msporny@digitalbazaar.com>
Hey Manu,

I mostly agree with what is said below. Nevertheless I have some questions and comments to discuss further...

- I understand the intention of the dated profiles in view of a possible later version of RDFa. But I wonder whether, for a better usability, we should not introduce the TR structure for profiles, too, with dated and non-dated URI-s. Ie, the 'official' URI for the profile would be something like

http://www.w3.org/profiles/rdfa

and, at the moment, this is linked or redirected to 

http://www.w3.org/2011/profiles/rdfa

I am afraid that for many many people the dated URI is a nuisance, and may even be a cognitive problem: they might expect that, in 2015, there will be another profile. We should try to get a more appropriate and shorter URI...

Implementations would use the date-less URI. If an author wants to be 100% future proof, he/she could explicitly refer to the dated URI.

- Because there is some sort of a mixup with the different languages... I am not sure I have a clear picture here. I thought that we decided to have _one_ profile file valid for all host languages. If we do not do that, we get back to the issue of how would I decide whether a host language is XHTML or simply XML. Your proposal seems to say that there is one profile for everybody (ie, the Core) and then host languages might define their own default profiles. Is this what you meant?

- I think it would be worth discussing the exact choice of profile URI-s outside the group, too. I think it would be a good idea if you raised this issue on the SW Coordination Group as soon as possible. The RDF WG is just starting and we should get a feedback from the WG chairs on this and the direction we are taking here asap.

Adding some words to the CG about the profile management might also be useful. A feedback from, say, Tom Baker, might be useful in this respect...

- When we issue a last call, we will have to blog about this separately, to gain feedback on the management details...

See also below:

On Feb 9, 2011, at 19:46 , Manu Sporny wrote:

[snip]
> 
>>> RDF/RDFa Profile Management
>>> ---------------------------
>>> 
>>> 1. The profiles are modified on a consistent basis and do not
>>>   change very often (perhaps once every 1-2 years).
>>> 2. Prefixes and terms are managed by the Semantic Web Activity Lead,
>>>   who announces changes on some well-known mailing list prior to
>>>   each re-publication.
>>> 3. Prefixes and terms MUST NOT be /removed/ from dated profiles.
>>> 4. Prefixes and terms MAY be /updated/ if the new meaning of the
>>>   term or prefix is semantically backwards compatible with the
>>>   previous term or prefix.

I am not sure what that would mean. Do you mean that if, say, a term is redefined to a new URI, then there should be some sort of an OWL statement making those equivalent, or sub properties, or something like that?

I am a bit uneasy. I wonder whether we should not simply say that prefixes should not be changed.

>>> 5. Vocabulary maintainers are strongly discouraged from re-using
>>>   the same prefix for a new vocabulary performing the same purpose.
>>>   For example, if a new non-semantically-backwards-compatible version
>>>   of 'geo' is released, it SHOULD be named 'geo2' or 'geonext' (in
>>>   other words, the prefix for the new vocabulary SHOULD NOT be 'geo').
>> 
>> clarification on whether new dated profiles will be released or not, and
>> if so what restrictions apply?
> 
> New dated profiles will be released. These releases will almost always
> coincide with a revision of a language that uses them (such as when RDFa
> 2.0 is released, or when TURTLE is standardized, etc.).
> 
> I don't think we need new restrictions, as the same restrictions that
> apply to other default profiles (as outlined in the proposal) would
> apply to these new profiles.


I would add another point that says something like:

6. Vocabulary maintainers SHOULD include an 'Expires' header in the HTTP response when a profile is dereferenced via HTTP. RDFa processors MAY use this header to implement local caching of the profiles.

Cheers

Ivan

> 

----
Ivan Herman, W3C Semantic Web Activity Lead
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Received on Thursday, 10 February 2011 08:58:04 UTC

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