- From: Ivan Herman <ivan@w3.org>
- Date: Mon, 18 Jun 2012 21:33:28 +0200
- To: Egor Antonov <elderos@yandex-team.ru>
- Cc: Dan Brickley <danbri@danbri.org>, Guha <guha@google.com>, Peter Mika <pmika@yahoo-inc.com>, Martin Hepp <martin.hepp@ebusiness-unibw.org>, "public-vocabs@w3.org" <public-vocabs@w3.org>, Jeni Tennison <jeni@jenitennison.com>
Egor, I wonder whether you did not make the same mistake as I did when the this idea came up at a workshop in Mountain View last year. My understanding of the proposal is do to something like: <... itemtype="http://schema.org/SomeType"> <link itemprop="additonalType" href="http://someuriforatype"> <...> Ie, there is no 'fork' of the microdata syntax. It is one more property in the schema.org space. (Dan or Guha, please correct me if my understanding is wrong.) Cheers Ivan --- Ivan Herman Tel:+31 641044153 http://www.ivan-herman.net (Written on mobile, sorry for brevity and misspellings...) On 18 Jun 2012, at 20:31, Egor Antonov <elderos@yandex-team.ru> wrote: > Using this property we do break microdata compatibility, because it's no longer microdata standard, but already such unofficial and undescribed fork. > No parser will parse it without some coding work, no verifier tool can verify schema match, because it won't be microdata anymore. > You propose to say "if you use microdata and want multiple itemtypes, use microdata with some hack" > I propose the same thing, but naming it direct. > It's just a superset of microdata features, and it can be implemented in a prettier way than "additionalType" property IMHO > Or my logic is wrong? > > 18.06.2012, 21:46, "Dan Brickley" <danbri@danbri.org>: >> On 17 June 2012 00:41, Guha <guha@google.com> wrote: >> >>> My personal preference is to just add an attribute called type (or >>> additionalType) which is samePropertyAs rdfs:type and be done with it. >> >> I've come to the same view; see proposal below. >> >> I've just spent a little while trying to answer my "What would break?" >> question, ... if we went the other way and extended Microdata. My >> conclusion is that the safest and most responsible option is to define >> http://schema.org/additionalType as a convenience alias for W3C's >> http://www.w3.org/1999/02-22-rdf-syntax-ns#type property. If Microdata >> was purely a syntax, maybe we'd be ok. But there is also another spec, >> the Microdata DOM API. Some software, e.g. Opera-based browsers, have >> been shipping with Microdata DOM API for a while. Others, like >> Firefox, have just added support. >> >> http://my.opera.com/ODIN/blog/2011/12/06/hello-opera-11-60 >> http://dev.opera.com/articles/view/microdata-and-the-microdata-dom-api/ >> https://twitter.com/FirefoxNightly/statuses/210300933056380928 >> https://bugzilla.mozilla.org/show_bug.cgi?id=591467 >> >> I made some tests with Opera 12, using >> >> <section itemscope itemtype="http://schema.org/CreativeWork >> http://schema.org/Cat"> >> <h1 itemprop="name http://example.com/fn">Hedral</h1> >> <p itemprop="description >> http://purl.org/goodrelations/v1#description">Hedral is a male >> american domesticshorthair, with ...</p> >> </section> >> >> ...but couldn't retrieve the DOM node when multiple types (of any >> kind) were present. Looking at the Firefox Bugzilla entry, there is >> also active discussion there of multiple item types - not clear even >> if basic multi-typing is supported yet. >> >> While we could choose to read this as "microdata API implementations >> are still catching up with the current html spec, so more changes >> wouldn't matter", I think the correct lesson is that we shouldn't >> casually mess with markup design that could have complex and >> un-analyzed impact on associated APIs. Browser makers will not >> appreciate changes at this time, and it will be costly and >> unproductive to try to persuade them. Any changes to Microdata would >> have to include not only rules for the syntax, but a corresponding API >> redesign, including failure conditions, new test cases etc., not to >> mention the energy and engagement needed to persuade all relevant >> stakeholders to accept the new model. >> >> I just don't think it's feasible, so let's try to do the best we can >> with 'additionalType'. >> >> A concrete proposal: >> >> Property: additionalType >> samePropertyAs: rdf:type >> description: "An alias for the rdf:type relationship between something >> and a class that the thing is in. It is generally preferable to use >> syntax-native typing mechanisms. The additionalType construct can be >> useful in constrained syntaxes - e.g. microdata - where multiple types >> from >> independent vocabularies cannot be easily expressed. In such >> situations, care should be taken to assign the most relevant >> schema.org type using >> the primary (e.g. 'itemtype') typing syntax. Schema.org tools may have >> only weaker understanding of extra types, in particular those defined >> externally." >> >> Peter & co. - can you live with that? >> >> Dan > > -- > Egor Antonov > http://staff.yandex-team.ru/elderos
Received on Monday, 18 June 2012 19:33:51 UTC