Re: [css-writing-modes-3] range limit for 'text-combine-upright: all' versus 'text-combine-upright: digits <integer>'

> On 23 Jun 2015, at 18:45, Koji Ishii <kojiishi@gmail.com> wrote:
> 
> On Jun 23, 2015, at 03:13, Gérard Talbot <www-style@gtalbot.org> wrote:
>> 
>> Le 2015-06-22 14:03, Florian Rivoal a écrit :
>>>> On 22 Jun 2015, at 11:35, Koji Ishii <kojiishi@gluesoft.co.jp> wrote:
>>>>> There seems to be no implicit (and no explicit) range limit to the number of consecutive characters when using 'text-combine-upright: all' but there is a range 2-4 limit with 'text-combine-upright: digits n':
>>>>> Q1: is that assumption correct? (To me, this seems odd and incoherent.)
>>>> Correct.
>>>>> Q2: If there is no range limitation with 'text-combine-upright: all', then
>>>>> why should there be one with 'text-combine-upright: digits n' where 'n'
>>>>> would be a [2-9] digit?
>>>> “all” is not likely to be affected much by the number of characters; it just measure the whole string, and shrink if needed.
>>>> “digits” checks the number of characters, and thus could fail on specific number. A request was made to avoid implementations and testing that were never used in the real world.
>>> I agree with Gérard.
>>> I understand wanting to limit to 4 digits since there is no use case
>>> for more if that makes implementations simpler.
>>> I do not understand why the logic is not applied to the all value,
>>> allowing it to only match up to 4 digits.
>> 
>> Yes. Exactly what I thought. Thank you Florian.
> 
> “all” is only about scaling. We don’t limit, for instance, transform: scale() even if scale factor such as 1,000,000 won’t be used at all, right?
> 
> On the other hand, “digits" value has two effects; limits number of characters to apply, and when apply, it scales by 1em/width.

I understand that that's what they do. But why?

 - Florian