Re: role mapping rules when context is broken

Hey.

On Tue, Nov 3, 2015 at 1:02 PM, Joseph Scheuhammer <clown@alum.mit.edu>
wrote:

> Hi Alex,
>
> On 2015-11-03 11:46 AM, Alexander Surkov wrote:
>
>> Hi, Joseph. I'm good to have a generic role
>>
>
> Cool.
>
>
> , but in general I don't see the benefits of having an accessible for it
>> as long as some generic ARIA attributes are not applied to it.
>>
>
> Neither do I.  If the element is truly "semantic free" -- no aria, no
> events, and completely insignificant -- then it could be left out of the
> tree.  I just thought that it was too much of a performance hit to
> determine that it's a nothing.
>

There's a bunch of things to check, that may affect on perfromance. On the
other hand keeping no-semantics elements bloats the tree. You may want to
let the browser to decide.


>
> There's a similar error regarding abstract roles and their mapping. The
>>> rule there is that browsers MUST NOT map an abstract role [2, item 2], but
>>> it doesn't say what to do.  It looks like FF gives uses the element's role
>>> mapping in that case.  For example, <p role="command"> is mapped as
>>> ROLE_PARAGRAPH, and <div role="command"> is mapped as ROLE_SECTION.
>>>
>> Iirc I argued about this rule in the past. It's extra work for the
>> browser to ignore these roles and there's no point for the user to use
>> them. I believe those roles should fall into ordinal unknown role
>> processing.
>>
>
> I'm not sure what you mean by "ordinal unknown role processing". Are you
> referring to the case where the role's value is unknown?  In that case, the
> directive is to fall back on the element's role, according to item 3 in the
> role mapping general rules [1].


there are different mechanism to expose the role, for example, MSAA's
acc_getRole returns the element's native role, while IA2's xml-roles object
attributes returns 'unknown' role. It'd be good if the spec had a comment
for that if that implementation doesn't contradict to the ideas expressed
by the spec :)


>   If that's what you mean, I could add wording to that effect to the
> abstract role case (item 2).
>

yep, it'd be awesome.


>
> Thanks.
>
> [1]
> http://w3c.github.io/aria/core-aam/core-aam.html#roleMappingGeneralRules
> (Item 3)
>
>
> --
> ;;;;joseph.
>
> 'Array(16).join("wat" - 1) + " Batman!"'
>            - G. Bernhardt -
>
>