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RDF Web Apps WG telecon minutes for 2011-10-13

From: Manu Sporny <msporny@digitalbazaar.com>
Date: Thu, 13 Oct 2011 12:54:02 -0400
Message-ID: <4E9717AA.8070408@digitalbazaar.com>
To: RDFa WG <public-rdfa-wg@w3.org>
Thanks to Stéphane for scribing! The RDF Web Apps WG telecon minutes for 
October 13th, 2011 are now available here:

http://www.w3.org/2010/02/rdfa/meetings/2011-10-13

If you would like to read minutes from this or previous meetings, the
public record of all RDF Web Apps WG telecons is available here:

http://www.w3.org/2010/02/rdfa/wiki/Meetings

Full text log follows:

----------------------------------------------------------------------------
Agenda
   http://lists.w3.org/Archives/Public/public-rdfa-wg/2011Oct/0020.html
Seen
   Gregg Kellogg, Henri Bergius, Knud Möller, Manu Sporny,
   Niklas Lindström, Sebastian Germesin, Shane McCarron,
   Stéphane Corlosquet
Guests
   Niklas Lindström, Henri Bergius
Scribe
   Stéphane Corlosquet
Resolutions
   1. Do not add functionality to @typeof where if the first token is an
      IRI, that sets the default vocabulary for processing.
Topics
   1. ISSUE-111: Determine behavior when @inlist and @rev are used
      together
   2. ISSUE-108: Refine/deprecate Link relations
   3. First IRI in @typeof determines the vocabulary used
   4. Schema.org supports RDFa in Rich Snippet Tool

(Scribe set to Stéphane Corlosquet)
(No events recorded for 11 minutes)

1. ISSUE-111: Determine behavior when @inlist and @rev are used together

Manu Sporny: has anyone implemented @inlist or @rev in their processor?

Gregg Kellogg: I didn't include it yet... @rev, when used with @inlist, 
has no effect in the current spec.

Niklas Lindström: the idea was that @rev used with @inlist might be 
useful to make a link back to the list itself

... it might introduce problems, though - you can only make reverse 
links to resources, not literals.

Manu Sporny: Ivan has implemented something, but there are issues with 
how to interpret that with other RDFa attributes?

Gregg Kellogg: @rev not doing anything with @inlist is not a proposal, 
it's the existing behavior. question is: do we want to keep it that way?

... if we don't have an advocate for @inlist we can't make much progress 
today.

Manu Sporny: Ivan would be that advocate, though he said he didn't 
really like what it did.

Manu Sporny: The danger is we have an attribute which does not do what 
we expect it to do. @rev works in every other case in RDFa, so why not 
with @inlist?

Manu Sporny: one can argue that @inlist it's an advanced feature, and 
should only be used for advanced use cases

Niklas Lindström: I agree. haven't seen any use case for using the list 
as a subject - no use cases for @rev and @inlist.

... if there were a real use case for it, we could supply the list as 
subject

... we should postpone it until a real use case is found

Manu Sporny: it seems people feel uncomfortable with @inlist and @rev 
used together

Manu Sporny: anyone disagree?

Manu Sporny: We should not make a decision on this call today - let's 
wait until Ivan and Toby can give their input.

Sebastian Germesin: ok, for waiting
Shane McCarron: You could send out a proposal to take effect in 7 days 
if nobody objects.

Shane McCarron: we should solicit Jeni's opinion

ACTION: Manu to write proposal to not support @rev/@inlist to not 
support for 7 days cc Jeni Tennison.

Trackbot IRC Bot: Created ACTION-98 - Write proposal to not support 
@rev/@inlist to not support for 7 days cc Jeni Tennison. [on Manu Sporny 
- due 2011-10-20].
2. ISSUE-108: Refine/deprecate Link relations

Manu Sporny: http://www.w3.org/2010/02/rdfa/track/issues/108
Manu Sporny: one approach we can take it accept only the values 
specified by HTML5

Manu Sporny: another approach is that the initial list could be the same 
as the XHTML values we have now, and wait until the new values are 
standardized to add them

Manu Sporny: another approach is to remove stylesheet, since those 
triples are not really useful and people don't like them.

Gregg Kellogg: The Microdata spec removed alternate and stylesheet and 
replaced them with ALTERNATE-STYLESHEET
Manu Sporny: maybe we should also remove alternate as it's not used the 
way we would expect it in RDF

Shane McCarron: alternate has valid use cases, linking to RSS documents, 
for instance.

Gregg Kellogg: Microdata used to do this in an earlier version of the 
spec: ALTERNATE-STYLESHEET

Shane McCarron: we don't care about the RDF generated by stylesheet

Manu Sporny: We could hold off on generating alternate or stylesheet 
triples until the processer would have processed all values in @rel to 
decide what value should be generated... alternate, stylesheet, or 
alternate-stylesheet

Manu Sporny: we want to generate useful triples for people on the 
semantic web. stylesheet and alternative are usually not useful.

... people who need these would not use RDF for the purpose of 
alternative and stylesheet, they would use a different type of 
application framework.

Niklas Lindström: .. I agree: stylesheet without content is reasonably 
quite useless
Niklas Lindström: .. i.e. without the html
Manu Sporny: Shane made a point not to remove alternate as it can link 
to alternate representation (RSS)

Niklas Lindström: we could also say that if @rel contains stylesheet we 
would ignore the @rel

Manu Sporny: is anybody depending on @rel alternate? I would be 
surprised if there was any, but have no data to back that up.

Niklas Lindström: I think there is a potential for it, I would probably 
use dc:hasFormat for that use case though

Manu Sporny: RDFa has been around since 2008, if today there is no use 
case today, there probably won't be - we should remove it.

Manu Sporny: in the vast majority of the use case, it generates the 
wrong triples anyway. HTML->alternate->CSS is flat out wrong.

Shane McCarron: on ALTERNATE-STYLESHEET: collection of value in the 
vocab document. if the HTML WG is randomly introducing new terms with 
semantics, there is potential for conflicts. e.g. role. is anyone 
worried about that?

Manu Sporny: we would raise an issue in the HTML WG if this were to happen

... that's all we can do, depend on W3C Process to prevent screw-ups 
like that.

Manu Sporny: the only thing we're talking about is the removal of 
stylesheet and alternate

Manu Sporny: anyone disagree? or want to add something?

ACTION: Shane to respond to mailing list with pointer to discussion 
today about alternate/stylesheet

Trackbot IRC Bot: Created ACTION-99 - Respond to mailing list with 
pointer to discussion today about alternate/stylesheet [on Shane 
McCarron - due 2011-10-20].
3. First IRI in @typeof determines the vocabulary used

Manu Sporny: 
http://lists.w3.org/Archives/Public/public-rdfa-wg/2011Oct/0016.html
Stéphane Corlosquet: I'm not the first one to propose this - some 
background. [ Scribe Assist by Manu Sporny ]
Stéphane Corlosquet: @vocab was introduced to make it easier to author 
content - to avoid using prefixes/CURIEs - so that was good, makes the 
markup easier. [ Scribe Assist by Manu Sporny ]
Stéphane Corlosquet: I think a burden remains - people that come from 
Microdata - there is a new concept that they have to understand - 
vocabularies. It's one more thing that people have to learn. [ Scribe 
Assist by Manu Sporny ]
Stéphane Corlosquet: Microdata solves this problem by just saying that 
the itemtype is the base vocabulary (implicitly). [ Scribe Assist by 
Manu Sporny ]
Stéphane Corlosquet: I was wondering if RDFa could adapt the same 
approach as Microdata - give the option of extracting the vocabulary 
from the first item in @typeof [ Scribe Assist by Manu Sporny ]
Stéphane Corlosquet: The only difference is that @vocab becomes optional 
- you can remove vocab and put the full URI of the type in @typeof... 
processors would infer the vocabulary from the first IRI in @typeof. [ 
Scribe Assist by Manu Sporny ]
Stéphane Corlosquet: We could allow for CURIEs in @typeof if the prefix 
is described somewhere in the document. [ Scribe Assist by Manu Sporny ]
Stéphane Corlosquet: So you could have something like 
typeof="skos:Concept" and then the skos URL would become the default 
@vocab. [ Scribe Assist by Manu Sporny ]
Gregg Kellogg: I was uncomfortable with this feature in Microdata... in 
RDFa it seems dangerous - it doesn't solve all of the problems you want. 
It's common to use properties from other vocabs like Dublin Core with 
schema.org - it seems unnatural for RDFa to be able to do that. [ Scribe 
Assist by Manu Sporny ]
Gregg Kellogg: RDFa just has other mechanisms to make this easier. [ 
Scribe Assist by Manu Sporny ]
Stéphane Corlosquet: I'm not saying RDFa should drop everything else, 
just add this to make markup easier for those coming from a Microdata 
world. [ Scribe Assist by Manu Sporny ]
Stéphane Corlosquet: This is just a shortcut to not use @vocab. [ Scribe 
Assist by Manu Sporny ]
Stéphane Corlosquet: The idea is that people that come from Microdata 
could make the change easily. It's just a search/replace. [ Scribe 
Assist by Manu Sporny ]
Niklas Lindström: I think I agree with Toby - who proposed this 
initially, and has since come around to not supporting this feature. 
There are problems with this approach - like what happens when you do 
chaining - there are technical issues. [ Scribe Assist by Manu Sporny ]
Niklas Lindström: This might be a bit too magical, rather than the 
explicit use of @vocab. [ Scribe Assist by Manu Sporny ]
Stéphane Corlosquet: I don't know if there is a problem with @vocab. re: 
Chaining - I believe that Microdata use cases will not use that. Raising 
this proposal from Microdata perspective. This is so that people can 
convert Microdata to RDFa easily. This feature will only be used with 
simple markup. [ Scribe Assist by Manu Sporny ]
Manu Sporny: aq+
Niklas Lindström: I kind of see your point - but there are issues. If I 
use full IRIs with this mechanism, that would also set the @vocab. 
@vocab specifies the namespace - but so does @typeof... that may be 
confusing - that's what Microdata kinda does. [ Scribe Assist by Manu 
Sporny ]
Manu Sporny: How do we know how to process the @typeof IRI in a 
deterministic way?
Manu Sporny: Is conversion from Microdata to RDFa a use case we care about?
Niklas Lindström: How is the vocabulary determined? [ Scribe Assist by 
Manu Sporny ]
Gregg Kellogg: Everything after the slash or hash - which is different 
from Hixie's spec. [ Scribe Assist by Manu Sporny ]
Niklas Lindström: Yes, this is aligned with schema.org - that's what 
you'd expect. [ Scribe Assist by Manu Sporny ]
Gregg Kellogg: and this is why we did it that way. [ Scribe Assist by 
Manu Sporny ]
Niklas Lindström: Microdata dropped any conversion to RDF... where are 
we on that? [ Scribe Assist by Manu Sporny ]
Gregg Kellogg: 
https://dvcs.w3.org/hg/htmldata/raw-file/24af1cde0da1/microdata-rdf/index.html#generate-the-triples 

Gregg Kellogg: HTML Data TF has responsibility to document how to 
convert Microdata to RDF. [ Scribe Assist by Manu Sporny ]
Niklas Lindström: This is an issue, no? <div 
vocab="http://purl.org/dc/terms/"><div typeof="bibo:LegalDocument"><p 
property="title">
Manu Sporny: it is not if you don't know that you can use @vocab

Manu Sporny: I don't know if we should care about this use case, if 
people have a reason to migrate from Microdata to RDFa, they will find a 
way to do it. Having to learn about the concept of a vocabulary doesn't 
seem like a high barrier to me. It may be dangerous to do a global 
search/replace of @itemtype with @typeof. [ Scribe Assist by Manu Sporny ]
Stéphane Corlosquet: I agree if you know that @vocab exists - it's not a 
problem... but if you don't know it exists - then it's difficult to 
learn that new concept. [ Scribe Assist by Manu Sporny ]
Stéphane Corlosquet: However, with this, it's not as confusing - people 
don't have to learn about @vocab - they just use @typeof. [ Scribe 
Assist by Manu Sporny ]
Manu Sporny: The mechanism to break the Microdata IRI into vocab is 
confusing, they'd have to learn that algorithm instead of @vocab. They 
already have to understand that there is a vocabulary somewhere. [ 
Scribe Assist by Manu Sporny ]
Stéphane Corlosquet: RDFa has a mixture of attributes to be added to 
markup - in Microdata you just have @itemtype... in RDFa you have @vocab 
and @typeof. [ Scribe Assist by Manu Sporny ]
Manu Sporny: Ok, we have discussed this thoroughly enough - is there any 
other information that we would need to understand to make an educated 
straw-poll on this item? [ Scribe Assist by Manu Sporny ]
PROPOSED: Add functionality to @typeof where if the first token is an 
IRI, that sets the default vocabulary for processing.

Gregg Kellogg: -1
Knud Möller: -1
Sebastian Germesin: +1
Niklas Lindström: -1
Shane McCarron: -1
Stéphane Corlosquet: +1

Manu Sporny: -1
RESOLVED: Do not add functionality to @typeof where if the first token 
is an IRI, that sets the default vocabulary for processing.

4. Schema.org supports RDFa in Rich Snippet Tool

Manu Sporny: Good news, schema.org supports RDFa in the Rich Snippet 
Testing Tool now. Let's all try to support them in implementing RDFa for 
schema.org
http://openspring.net/blog/2011/09/30/schemaorg-rich-snippets-drupal-7-rdfa

--manu

-- 
Manu Sporny (skype: msporny, twitter: manusporny)
Founder/CEO - Digital Bazaar, Inc.
blog: Uber Comparison of RDFa, Microformats and Microdata
http://manu.sporny.org/2011/uber-comparison-rdfa-md-uf/
Received on Thursday, 13 October 2011 16:54:39 GMT

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