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Re: noted 3 issues re: time/data (was Re: minutes for HTML WG f2f, 2011-11-04, part 1)

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Fri, 18 Nov 2011 09:51:56 -0800
Message-ID: <CAAWBYDDP1fdtt-EzV6+hXNNPxcUbfq8qJ3UE5y29pLUBiUU6bQ@mail.gmail.com>
To: "Marat Tanalin | tanalin.com" <mtanalin@yandex.ru>
Cc: Philip Jägenstedt <philipj@opera.com>, Tantek Çelik <tantek@cs.stanford.edu>, Sam Ruby <rubys@intertwingly.net>, public-html@w3.org
On Fri, Nov 18, 2011 at 9:22 AM, Marat Tanalin | tanalin.com
<mtanalin@yandex.ru> wrote:
> 18.11.2011, 19:59, "Philip Jägenstedt" <philipj@opera.com>:
>> We cannot provide equivalent markup for itempropvalue unless we know how
>> itempropvalue is intended to work:
>>
>> 1. When itempropvalue appears on an URL property elements [1], is it (1)
>> ignored (2) resolved as a URL or (3) a plain text property?
>
> For URL property elements, @itempropvalue attribute should probably be ignored since such elements have their own dedicated attributes to store a value.

That's even worse, imo.  @itemscope already "wins" over special
attributes when they're specified together (in other words, in <a
itemprop=foo href=bar itemscope>, the value of "foo" is the nested
item, not the url).  If @itempropvalue instead lost to the special
attributes, that would be all kinds of confusing.


>> 2. When itempropvalue appears together with itemscope, is it (1) ignored
>> or (2) a plain text property?
>
> @itempropvalue should be treated according to @itemtype. If @itemtype defines that item value should consist of several values specified by child elements, then @itempropvalue for element with @itemscope attribute should probably be ignored.

The Microdata extraction algorithm doesn't pay attention to the
itemtype when extracting.  It *can't*, because there's no schema for
indicating such a structure in a machine-readable way, there's no way
to link the itemtype to a schema in a machine-followable way, we know
from long experience that adding such a mechanism (see DOCTYPEs) is an
invitation to DDOS the provider, and finally, if the resource is ever
unavailable, either temporarily (site overwhelmed) or permanently
(domain registration expired), the extraction algorithm would have no
way to know what to do.

Now, *after* the data's been extracted, a type-aware consumer can
interpret the data however they like.  They've got the schema
built-in, so none of the above problems affect them.

~TJ
Received on Friday, 18 November 2011 17:52:48 UTC

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