Re: ISSUE-366 (condition vs xml:id): xml:id uniqueness needs to be broken for some uses of condition [TTML2]

On Fri, Jan 16, 2015 at 5:11 PM, Glenn Adams <glenn@skynav.com> wrote:
>
>
> On Fri, Jan 16, 2015 at 8:48 AM, Silvia Pfeiffer <silviapfeiffer1@gmail.com>
> wrote:
>>
>> On 16 Jan 2015 16:31, "Glenn Adams" <glenn@skynav.com> wrote:
>> >
>> >
>> > On Fri, Jan 16, 2015 at 8:01 AM, Silvia Pfeiffer
>> > <silviapfeiffer1@gmail.com> wrote:
>> >>
>> >>
>> >> On 16 Jan 2015 15:40, "Nigel Megitt" <nigel.megitt@bbc.co.uk> wrote:
>> >> >
>> >> > From: Glenn Adams <glenn@skynav.com> Date: Friday, 16 January 2015
>> >> > 14:33
>> >> >
>> >> >> We could also upgrade @region to IDREFS, like @style, in which case,
>> >> >> if more than one of the referenced regions is semantically active, i.e.,
>> >> >> condition is not false on multiple referenced regions, we could define
>> >> >> behavior as one of:
>> >> >> use the first (and only first) referenced region that is
>> >> >> semantically active;
>> >> >
>> >> > Seems like a good idea, as a minimum.
>> >> >>
>> >> >> select the content into all referenced regions that are semantically
>> >> >> active;
>> >> >
>> >> > I don't know a use case for this.
>> >>
>> >> FWIW: on the web, ID is semantically supposed to point to 1 or 0
>> >> elements, not to more. I'd highly recommend for the first option to avoid
>> >> confusions.
>> >
>> > The distinction is between IDREF and IDREFS. The former points exactly
>> > one element (not zero).
>>
>> [FWIW: It's zero if the target does not exist.]
>
>
> ah, that would be fail XML (let alone schema) validity, so we don't have to
> consider that case since it is not semantically relevant
>
> Validity constraint: IDREF
>
> Values of type IDREF must match the Name production, and values of type
> IDREFS must match Names; each Name must match the value of an ID attribute
> on some element in the XML document; i.e. IDREF values must match the value
> of some ID attribute.

Sure. But applications also have to deal with invalid files. Not important.

>>
>> > The latter points at one or more elements.
>> >
>> > We already have a few attributes typed as IDREFS, such as @animate,
>> > @style, and @ttm:agent.
>> >
>> > The idea being discussed here is upgrading @region from IDREF to IDREFS
>>
>> No worries. I thought you wanted to keep it in sync with xml:I'd .
>
> Not sure what you mean here.
>

Not important either. I meant: keep in sync with the semantics of
xml:ID , but you're already discussing this.

Cheers,
Silvia.

Received on Friday, 16 January 2015 18:00:44 UTC