RDF in XHTML Task Force

06 Aug 2009


See also: IRC log, previous: http://www.w3.org/2009/07/30-rdfa-minutes.html


Manu Sporny, Mark Birbeck, Shane McCarron, Ben Adida
Michael Hausenblas, Steven Pemberton, Ralph Swick
Ben Adida
Manu Sporny



Action Items

<scribe> ACTION: Ben to summarize architectural issues (security) re: @profile proposal for tokenizing the web. [recorded in http://www.w3.org/2009/07/30-rdfa-minutes.html#action04] [DONE]

<scribe> ACTION: Shane to produce proposed diff re: XMLLiteral change [recorded in http://www.w3.org/2009/07/30-rdfa-minutes.html#action03] [CONTINUES]

<scribe> ACTION: Ben to author wiki page with charter template for RDFa IG. Manu to provide support where needed. [recorded in http://www.w3.org/2009/05/28-rdfa-minutes.html#action10] -- continues

benadida: have made some progress on that, got up early to work on it.

<benadida> worth reviewing --> http://rdfa.info/wiki/Rdfa-ig-charter

benadida: might want to have people start reviewing that now.
... Focuses around two activities.
... Provide input to HTML WG on RDFa.
... RDFa in XHTML v1.1
... The proposals we're making for simpler syntax (@profile, @token) will push us towards 1.1 for XHTML+RDFa
... Those are the two foci of the RDFa IG.

Continued @profile discussion


benadida: That's the summary of the issues...

markbirbeck: @profile is how do we find a bunch of tokens.

benadida: We didn't go too deep without you here, Mark.
... The security issue seems to have struck a chord with Manu and Shane.
... The parser now needs to dereference 3rd party resources and that is an issue with Javascript and XMLHttpRequest.

markbirbeck: Right.
... The substance of my proposal was about the tokenisation aspect.
... We should consider using the tokenization term.
... We should attempt to address the xmlns: issues that people have been concerned about.
... The issues that you are raising are with the mechanism of finding other tokens.

benadida: The question is where in the stack does the tokenization happen?

markbirbeck: I think tokenization does exist now.
... This is purely about languages that reflect RDF.
... You're saying that tokenization is part of the CURIE stack.
... Language (N3, RDF/XML) has its own way of expressing RDF.
... CURIEs do a pretty good job of summarizing URIs.
... Why not allow the syntax to not need colons for expressing CURIEs.

benadida: Right, so to be precise: In any implementation, where would it live?
... This would have to live in the layer above the RDF store...
... You have to resolve the CURIE into a URI before you put it into the RDF store.

Shane: Mark's proposal is in essence, in an existing RDFa document today, with a minor change to the processing model, you could declare a token mapping /in-line/ and then use that token mapping as a defined term.
... you could do something like <span token="shane=http://example.org/shane#" property="shane">Shane McCarron</span>

benadida: I think the common goal we want is the simpler syntax.

<ShaneM> <span xmlns:shane="http://www.halindrome.com/me" rel="shane">Shane McCarron</span>

Manu: These are separate issues, tokenization and @profile.

benadida: Well, what's the goal?

markbirbeck: So, there are a number of goals.
... One of them is that xmlns: is problematic.
... We're trying to make it easier to author.
... The big problem with Microformats was never really the syntax.
... The vocabularies don't scale.
... There isn't a unified parsing mechanism.
... The goal of tokenization is to provide Microformats-like markup.
... I'm proposing a solution for what we agree is a particular problem.
... Tokenization isn't an end in itself.
... it isn't.

<Zakim> ShaneM, you wanted to talk about why remote vocabs are a problem

ShaneM: I don't think anybody disagrees that we need to provide an easier markup mechanism.
... The issue isn't @token - it's that having collections of those terms expressed remotely in a way that is discoverable, is problematic
... it's problematic because we have issues with Javascript + XMLHttpRequest.

markbirbeck: Yes, I understand that.
... There are ways of loading remote URLs in Javascript.
... We still haven't addressed the conceptual question...
... There are conceptual issues about mapping at the RDF level.
... We need to get the conceptual level right.

benadida: I think we agree on the approach.
... I think it's a symptom of the conceptual issue.
... I think we're putting too much responsibility on the parser.
... The parser has to dereference 3rd party resources.
... It's a symptom of the larger issue.

markbirbeck: I fundamentally disagree with you.
... There is an issue - how do you get the document?
... But that doesn't tell you anything about the fundamental distinction.
... We have a way of mapping text to URIs.
... currently in RDFa.
... So, using owl:sameAs is problematic.
... All @token does is add a way of mapping text to URIs.

<markbirbeck> Slightly modify Shane's example, by adding a colon:

<markbirbeck> <span xmlns:shane="http://www.halindrome.com/me" rel="shane:">Shane McCarron</span>

markbirbeck: So, we can already to the markup above.
... When you're working out CURIEs, the above works.
... The proposal doesn't hinge on @profile or @token - it's just a way to use colon-less reserved words in @property/@rel/etc.

benadida: I don't think we can look at that goal separately from making the syntax simpler.
... If we're looking at the end-goal - looking at the proposal piece-meal doesn't help.

markbirbeck: What I want to stress is that the rdf:subproperty approach requires some mechanism to load an external document.

<benadida> google's markup:

<benadida> <div xmlns:v="http://rdf.data-vocabulary.org/#" typeof="v:Review">

<benadida> <p><strong><span property="v:itemReviewed">Blast 'Em Up</span>

<benadida> Review</strong></p>

<benadida> <p>by <span property="v:reviewer">Bob Smith</span></p>

<benadida> <p><span property="v:dtReviewed">March 20, 2009</span></p>

<benadida> <p><span property="v:description">This is a great game. I

<benadida> enjoyed it from the opening battle to the final showdown

<benadida> with the evil aliens.</span></p>

<benadida> <p><span property="v:rating">4.5</span> out of 5 stars</p>

<benadida> </div>

<benadida> <div prefix="http://rdf.data-vocabulary.org/#" typeof="Review">

<benadida> <p><strong><span property="itemReviewed">Blast 'Em Up</span>

<benadida> Review</strong></p>

<benadida> ...

benadida: You have to dereference at some point.
... But the key is, /when/ you do it.
... Mark, in your proposal, until you dereference the 3rd party resource, you've got nothing that you can do any processing on.

markbirbeck: If you went the @profile route, then yes, you are correct.
... There are different ways of doing it.
... One way is where @profile is hardwired or well-known.
... Your proposal achieves something different than where I see the whole Microformats-style going.

<ShaneM> Note that these two approaches (token and default prefix) are complementary.

markbirbeck: provided that they don't use any of the standard terms (such as next/prev/etc). Example: prefix: reference

markbirbeck: With your proposal, its very difficult to mix vocabularies.
... doing this is difficult if not impossible: profile="a=b c=d"
... with your proposal.

benadida: There is some way that we need to resolve these reserved words.
... To fully resolve it, I'd rather we delegate it to the RDF stack.
... Rather than pushing that functionality into the RDFa processor.
... Adding another layer of resolution in the parser is going to cause us more problems than solve issues.

markbirbeck: That is a separate discussion - how do we load other stuff.
... Even if you forget the owl:sameAs stuff.
... One issue is how we map things.
... how do we map yahoo's products to google's products.
... I'm not talking about that.
... I'm talking about simply the abbreviation mechanism.
... my criticism of your proposal, is that there are 2 major criticisms.
... one - you're using suffixes instead of tokens
... we came up with an algorithm in XHTML+RDFa so that you can distinguish those from values.
... problem two - you only solve the problem for one vocabulary in any given context.

benadida: problem one is a small weakness - I agree.
... problem two, I disagree with.
... Google can, in their schema, say v:title maps to dc:title

markbirbeck: What happens when I want to add properties from the Good Relations vocabulary?
... how can I mix vocabularies?

benadida: That's not a problem, it's a feature
... We're addressing authors that want to just use one vocabulary.

markbirbeck: We're getting to the crux of the problem we're trying to solve.
... Most may not understand how to mix vocabularies.
... Most of the work I'm doing requires that you use many, many vocabularies.
... We should work out what we're trying to achieve.

<Zakim> ShaneM, you wanted to disagree about what curies know about references and to mention that authors can create hybrid vocabs too

ShaneM: I disagree that CURIEs don't know about references.
... we built into a CURIEs a way to specify a default prefix.
... reserved words are also processed first.
... I think being able to set the default prefix can be enabled.

benadida: What are the next steps?

markbirbeck: There may be a way of harmonizing the two.

ShaneM: The two proposals are complimentary.

<ShaneM> I wonder if it is possible to define a hybrid "vocabulary" that encompasses all of the existing microformat terms?

markbirbeck: Ben, your proposal is that we enable default prefix.
... If we're happy that @token is resolved, then we may be able to enable default prefix.

benadida: Worried about teaching these features.

markbirbeck: I think we focus on the language elements that address the use cases.

<ShaneM> reserved terms are checked first in the RDFa processing model... If we permitted "tokens" then those would get evaluated before looking for a default prefix. Ben seems to agree with this.

benadida: I'm worried about the consequences to the stack with your solution... what role are we giving the parser.

Summary of Action Items

[PENDING] ACTION: Ben to author wiki page with charter template for RDFa IG. Manu to provide support where needed. [recorded in http://www.w3.org/2009/05/28-rdfa-minutes.html#action10]
[PENDING] ACTION: Shane to produce proposed diff re: XMLLiteral change [recorded in http://www.w3.org/2009/07/30-rdfa-minutes.html#action03]
[DONE] ACTION: Ben to summarize architectural issues (security) re: @profile proposal for tokenizing the web. [recorded in http://www.w3.org/2009/07/30-rdfa-minutes.html#action04]
[End of minutes]

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$Date: 2009/08/11 13:14:11 $