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Re: [css-syntax] An+B nits

From: Brad Kemper <brad.kemper@gmail.com>
Date: Sat, 22 Feb 2014 10:49:15 -0800
Message-Id: <7F1A02F9-18D3-4EC2-BC28-BB6D28B9B72E@gmail.com>
Cc: www-style list <www-style@w3.org>
To: Simon Sapin <simon.sapin@exyr.org>


Sent from my iPad

> On Feb 22, 2014, at 8:49 AM, Simon Sapin <simon.sapin@exyr.org> wrote:
> 
>> On 22/02/2014 16:39, Brad Kemper wrote:
>> In the An+B micro syntax section [1], I noted the following issues:
>> 
>> • Example 35 uses '-n', but only later is it explained that an 'n'
>> without a number before it is the same as 1n (thus '-n' means the same
>> as '-1n'). For example 35, it would be more clear at that point if it
>> was written as '-1n+6'. It would also be helpful IMO if there was also
>> an example there using a negative n that resulted in a list of more than
>> one item, such as:
>> 
>> –4n+10   /* represents the 6th and 2nd elements in the list */
>> 
>> By the way, would that be the right order of the results in the CSSOM,
>> or do they get sorted?
>> 
>> • the spec says that a negative 'n' is allowed, but it does not make it
>> clear how to write that. The text above examples 38 and 39 imply that
>> the minus sign can just replace the plus sign, but I think there should
>> be prose to that effect, such as in the opening paragraph of the syntax
>> section. Is it valid to also add a negative, as in '5n + -1'? I think
>> the grammar section says no, but I am not sure.
>> 
>> 1) http://dev.w3.org/csswg/selectors4/#anb
> 
> 
> I believe the plan is to remove that section and reference CSS Syntax instead: http://dev.w3.org/csswg/css-syntax/#anb

OK, changing the subject line, and noting that there is even less detail about this micro syntax there, where it also surfers from the same problems.

> Pseudo-classes can be though of as boolean tests.

Right. I should have thought of that.

> The sign of A in :nth-child(An+B) does not affect the order of Selector API results. (By the way, is that order specified at all?)

Good question.
Received on Saturday, 22 February 2014 18:49:51 UTC

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