W3C home > Mailing lists > Public > public-vocabs@w3.org > June 2012

Re: additionalType property, vs extending Microdata syntax for multiple types

From: Alexander Botero-Lowry <alexbl@google.com>
Date: Tue, 19 Jun 2012 14:08:57 -0700
Message-ID: <CAAuL=6Lp659zuQAfW55KdzREFTLrhMVXzBWsZiSpn2yOmczFwA@mail.gmail.com>
To: Stéphane Corlosquet <scorlosquet@gmail.com>
Cc: Egor Antonov <elderos@yandex-team.ru>, Martin Hepp <martin.hepp@ebusiness-unibw.org>, Dan Brickley <danbri@danbri.org>, Peter Mika <pmika@yahoo-inc.com>, "jasnell@gmail.com" <jasnell@gmail.com>, "public-vocabs@w3.org" <public-vocabs@w3.org>, Ramanathan Guha <guha@google.com>, Jeni Tennison <jeni@jenitennison.com>
On Tue, Jun 19, 2012 at 2:05 PM, Stéphane Corlosquet
<scorlosquet@gmail.com> wrote:
> On Tue, Jun 19, 2012 at 9:53 PM, Egor Antonov <elderos@yandex-team.ru>
> wrote:
>> Well, validators developers will not be very happy with this change.
>> However, if it happens, I prefer 'type' name, because 'additionalType'
>> implies there are other, non-additional ones.
> I disagree. 'type' would be misleading and imply that all types are set by
> this property, when it is not the case. Microdata and RDFa have simpler ways
> of setting the types of a data item. This new property should be used
> sparingly and for cases where the default microdata itemtype attribute is
> not sufficient. Note that it does not make much sense to be used in RDFa
> since mixing vocabularies for types is natively supported.


It's important to be explicit about additionalness because of the
requirement for the itemtype to be schema.org for this to work.

<div itemscope>
  <link itemprop="type" href="http://schema.org/Product">

is not equivalent to:

<div itemscope itemtype="http://schema.org/Product"></div>

Indeed, the first is not semantically useful, but the second is.

Received on Tuesday, 19 June 2012 21:09:27 UTC

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