Re: [css-ruby] spanning of ruby annotations across excess bases

On Sun, Nov 9, 2014 at 5:42 AM, L. David Baron <dbaron@dbaron.org> wrote:

> http://dev.w3.org/csswg/css-ruby/#base-annotation-pairing says:
>   # If there are not enough ruby annotations in a ruby annotation
>   # container, the last one is paired with (spans across) any excess
>   # ruby bases. (If there are not any in the ruby annotation
>   # container, an anonymous empty one is assumed to exist.)
>
> Is there actually a use case for this behavior, or is it really just
> defining error handling?
>

I guess they have, for example, an English word spans several kanji along
with their kana. Or a multi-kanji word with two different pronunciation,
one for kun'yomi, the other for on'yomi.

I ask because I think it adds substantial extra complexity,
> especially around line-breaking of ruby.  If there isn't a good use
> case for it, I would prefer if ruby annotation containers that do
> not have enough annotations simply not provide annotations for the
> final bases, instead of having their final annotation span all the
> remaining bases.


I want to add that, the spanning rule here not only increases the
complexity on line-breaking, but also make it difficult to define space
distribution behavior for alignment. You can see issue 9 in the current
draft.

I agree with David that we should get rid of the complexity of spanning,
because any spanning effect can be achieved by this pairing rule can also
be done by nested ruby. In addition, spanning is rarely used. In JLREQ, I
found only one usage (Fig. 3.61) which, as the document mentions, is very
rare.

Also cc international group for this discussion. They should have deeper
understanding of the usage of ruby.

- Xidorn