Fix mapping of doc-subtitle as a heading

[mattgarrish]

We created doc-subtitle because there wasn't a way to associate a heading and subtitle at the time, but also understanding that this was an issue that APA needed to address with the HTML folks.

But now that the document outline algorithm has been fully removed from HTML, and hgroup redefined to allow a p tag for subtitles, I'm not sure there's a need for this role anymore. The association between heading and subtitle can be relayed by the hgroup, so having this role may be redundant.

doc-subtitle also maps to a numberless heading, which I'm not even sure really works for its intended purpose of not being a heading that would intrude in the document heading structure. We wanted publishers to not repeat numbered heading tags for subtitles, but the solution probably does not solve the problem here.

So does it make sense to deprecate this role?

[pkra]

Related:

• Proposal: role="subheading" aria#1378
• Making p in hgroup align with the html specification html-aam#501

[mattgarrish]

Thanks for the references @pkra !

Another good point in those threads is that hgroup only allows one heading, so absent a change to doc-subtitle's mapping it seems to be a violation to put the role on a p tag in the element. One more way it's a mess right now.

[scottaohara]

from some limited testing from awhile ago, the numberless heading approach just gets 'corrected' to be an h2.

it'd be nice if the mapping could be revised to not be a heading, but maybe instead pull from paragraph (to follow suit with HTML's updated hgroup) and then have something like an xml-roles:subheading to change the roledescription.

or maybe that'd break some docs that are relying on the headingness (if 'checkedness' is a word, then so is this 😄)of subtitle and we do something like the above per the linked aria issue of creating a subheading role?

[mattgarrish]

or maybe that'd break some docs that are relying on the headingness

I don't expect that would happen for ebooks. We wanted the role so that we wouldn't have subtitles as headings, and I don't expect most publishers using the role understand what is happening at this level.

If we could change the mapping to dissociate the role from a heading that could also work. I don't think it's harmful to have the role even with the existence of hgroup; I'm just not sure how necessary it is and in its current state it stands to cause more problems than it solves.

[scottaohara]

hgroup doesn't do anything special for p - but if the mapping of docsubtitle changed, then it could be used to revise the mapping for the p element, and allow people do just use the p element, or an elemetn with doc-subtitle role.

but this would make this into an issue with dpub aam, rather than dpub aria

[mattgarrish]

but this would make this into an issue with dpub aam, rather than dpub aria

I'll transfer this across to the other repository and change the title to something more specific about the current mapping.