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Re: ISSUE-147 (preserve markup by default): RDFa Processors should preserve markup by default [RDFa 1.1 in HTML5]

From: Ivan Herman <ivan@w3.org>
Date: Sat, 29 Dec 2012 21:04:19 +0100
Message-Id: <21156255-D018-48DF-87F2-DE450C8DC9E0@w3.org>
Cc: RDFa Working Group <public-rdfa-wg@w3.org>
To: Sebastian Heath <sebastian.heath@gmail.com>

I am sorry not to have the time to go into the details of your use case right now. But I wanted to make a quick point. You seem to suggest that HTMLa+RDF Lite could retain the current handling of XML or HTML Literal, ie, not to generate those unless explicitly instructed through a @datatype usage, whereas the non-lite version could have the opposite behaviour. Is it what you suggest? I am afraid that would not fly if this is indeed what you propose. Indeed RDFa Lite is not a different language with different processing rules. It is only an editorial subset, so to say, reducing the number of attributes that are used. The current structure does not allow defining a different processing for Lite and for non-lite.


Ivan Herman
Tel:+31 641044153

(Written on mobile, sorry for brevity and misspellings...)

On 29 Dec 2012, at 20:47, Sebastian Heath <sebastian.heath@gmail.com> wrote:

> On Sat, Dec 29, 2012 at 8:25 AM, Ivan Herman <ivan@w3.org> wrote:
>> I agree with you and Gregg. The issue on XML Literal has been discussed a
>> lot. It wasn't an obvious issue, but the decision has been made.
>> Procedurally, it is correct to say that this WG has the right to define the
>> behaviour of HTML5+RDFa differently for XML Literals and/or for HTML
>> literals. However, the discussions for RDFa Core, as well as for
>> XHTML1+RDFa, obviously took into account the most important prospective
>> deployment of RDFa, i.e., HTML5, too. I also do not see any new evidence in
>> this thread that would justify essentially reopening this issue, and
>> introducing a major incompatibility between XHTML1, SVG, etc., and HTML5. I
>> am sorry, Andreas, but I am definitely not in favour of this change.
>> Ivan
>> ---
>> Ivan Herman
>> Tel:+31 641044153
>> http://www.ivan-herman.net
>> (Written on mobile, sorry for brevity and misspellings...)
> Ivan,
> Thank you for your response. And thank you for clarifying that the WG
> can adapt the RDFa 1.1 Core document to the specific needs of an
> (X)HTML5 context, though I'm sure we all agree that that is inherent
> in the process of describing how RDFa works in a host language.
> And again thank you for indicating that there is a requirement for
> new evidence. I am not sure why that is the case since this is a new
> issue opened on "RDFa 1.1 in HTML", but if that requirement does
> exist, I believe this situation meets it. Of course, that keeps us on
> procedural issues, which are less interesting than the basic point of
> making sure "RDFa 1.1 in HTML" is a well-constructed and robust spec
> that can meet the needs of many users. But since the objections to
> considering ISSUE 147 seem to be procedural, I'll address those.
> New Evidence:
> * The existence of RDFa Lite
>    When the decision to discard child elements when distilling RDF
> triples from RDFa+XML was made (ISSUE 19) [1], RDFa Lite did not exist
> [2]. This is relevant because it seems that a reason for discarding
> child elements is how "semantic data is consumed in the marketplace"
> [3].
> I believe I'm on fairly firm ground in saying that one inspiration
> for RDFa Lite was to ease the process by which semantic data is
> firstly created and secondly consumed in an SEO oriented
> "marketplace". Although I do not use RDFa Lite, I fully recognize its
> need and utility. But to the extent that one downstream use of
> semantic data is determining default behaviors, I suggest we can now
> encapsulate those behaviors in RDFa Lite. Meaning, that RDFa Lite can
> retain the default production of Plain Literals when processing HTML5.
> In fact, I think that is a perfect use of RDFa Lite, one that was not
> possible when ISSUE 19 was decided. This should not lead to ISSUE 19
> being re-opened, but rather the current ISSUE 147 being considered on
> its merits.
> * Use cases in which child elements in (X)HTML5 are not a mistake
> I think that such uses can be considered new evidence has already been
> recognized by Manu's inclusion of point 2 in his list of items that
> the WG should re-examine [4]. So perhaps the following is also my
> contribution to that re-examination.
> Here's my use case and some of its history by way of explaining why I
> raised this issue now and in the context of "RDFa 1.1 in HTML5":
> As I said, I edit an online scholarly journal "ISAW Papers" [5]. The
> end result of the publication process will be the deposition of XHTML
> files in the New York University Faculty Digital Archive for permanent
> preservation. It is my hope to also use RDFa to encode the semantic
> data in these articles. I have begun to do so and an example of the
> current state of work can be seen in the publicly accessible version
> of ISAW Papers 2 as delivered by the NYU library [6]. If you look in
> the source of that page, you will see many @property values which have
> child elements, in particular, dcterms:bibliographicCitation. It is
> not a mistake that those are there, they are important, and it is
> important to me that they be preserved in workflows that process this
> data. That is the source of my request that ("non-lite") RDFa
> distillers preserve that markup.
> But in terms of procedure and the requirement for new evidence, here
> is where I am. For some time now I have been developing ISAW Papers
> with XHTML+RDFa 1.0, which did preserve child elements.  The RDFa Core
> Rec came out in June. THe community's attention turned more firmly to
> RDFa in HTML5, as did mine. In the fall I began converting my content
> to HTML5 and RDFa 1.1. (If you poke around ISAW Papers you'll see
> evidence of an ongoing process...) In making that conversion I saw
> that child elements where discarded.  This is a concern to me because
> I am hoping to encode my semantic data using RDFa 1.1, then use
> standardized tools that extract that semantic data, and then process
> that semantic data for both automatic-agent and human consumption. In
> all these cases, preservation of markup is extremely important.
> It did take me some time to confirm that the discarding of markup was
> not caused by error on my part. Knowing now that it is a feature of
> the REC, I have now reported my concern in the context of the "RDFa
> 1.1 in HTML5", and I have made this report while the spec is a Working
> Draft. I don't think it is unusual that I have found this issue only
> after taking considerable time to work with both specs and hope
> realities of my timing aren't determinative in addressing ISSUE 147.
> To put that another way, I think I have done the "right thing" in
> pursuing the conversion now and in offering my feedback to the WG.
> I do recognize that the development process for RDFa 1.1 Core looked
> forward to its deployment in HTML5. Ivan, you noted this above. But I
> do think its important that RDFa Core describes RDF in the context of
> generic XML documents and so did not bear the burden of fully
> addressing the role of RDFa in HTML5. This seems clear from the
> well-understood need for the "RDFa 1.1 in HTML5" product that we are
> working on now.
> * Accessibility
> I am not an expert in this topic so I raise it with some hesitancy.
> But I would like my XHTML to be accessible as defined by the W3's Web
> Accessibility Initiative [7]. I see there that it suggests the use of
> HTML markup to achieve its goals, see the suggested use of the dfn
> element [8]. It is likely that such elements will end up in RDFa
> marked content such as dcterms:abstract. The current "RDFa 1.1 HTML5"
> spec discards that accessibility markup. But let me clear, I defer to
> Shane's greater expertise or any other official feedback from the WAI
> on this issue.
> Ivan, on the basis of the above, I wonder if you would be willing to
> reconsider your determination that insufficient new evidence has been
> introduced in order to consider ISSUE 147 within its stated "RDFa 1.1
> in HTML5" context.
> Broadening this discussion slightly, in earlier messages I have made
> what I think are substantive points as to why either rdf:XMLLiteral or
> rdf:HTML should be the default production when parsing elements that
> have child elements. I won't repeat those here, other than to note
> that I highlighted issues of language, which I think are especially
> relevant as RDFa is deployed in HTML5. It looks like there was some
> consideration of language in the teleconference that resolved ISSUE
> 19, with the suggestion that this is where people might want markup
> preserved [9]. I agree and think "RDFa 1.1 in HTML5" is the right
> place to pursue that topic.
> To sum up with reference to previous messages:
> 1) The consideration of ISSUE 147 with in the context of the Working
> Draft of "RDFa 1.1 in HTML5" is timely.
> 2) There is new evidence in the form of the existence of RDFa Lite,
> the introduction of a use case in which child elements are not a
> mistake, full consideration of multi-lingual issues as they appear in
> HTML5 as used in the real world, and the possibility of WAI impact.
> 3) There is a substantive case for the default production of
> rdf:XMLLiteral and rdf:HTML in the context of HTML5 and its variants.
> See "2)" immediately above.
> 4) Some solutions have been offered in the form of: restricting the
> default discarding of markup to RDFa Lite in HTML5, writing separate
> specs for  RDFa inXHTML5 and HTML5, re-enforcing that elements
> without child markup should produce a Plain Literal.
> I do hope the above discussion allows us to move beyond procedural
> issues to full consideration of the merits of ISSUE 147.
> My final point is that I hope it's clear that this issue is of great
> importance to me. I want to use XHMTL+RDFa but this default
> behavior is a real impediment. One that I have only recently
> discovered. So I've tried to be clear in my
> language (though it's hard to be concise!). Please don't take
> that as abruptness or rudeness.
> Thank you,
> Sebastian.
> [1] http://www.w3.org/2010/02/rdfa/track/issues/19
> [2] http://www.w3.org/standards/history/rdfa-lite
> [3] http://lists.w3.org/Archives/Public/public-rdfa-wg/2012Dec/0077.html
> [4] http://www.w3.org/2010/02/rdfa/track/issues/147
> [5] http://isaw.nyu.edu/publications/isaw-papers
> [6] http://dlib.nyu.edu/awdl/isaw/isaw-papers/2/
> [7] http://www.w3.org/WAI/
> [8] http://www.w3.org/TR/2012/NOTE-WCAG20-TECHS-20120103/H54
> [9] http://www.w3.org/2010/02/rdfa/meetings/2010-05-13#ISSUE__2d_19__3a__Default_generation_of_XMLLiterals
Received on Saturday, 29 December 2012 20:04:43 UTC

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