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Re: [css3-conditional] Resolving issues

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Wed, 26 Sep 2012 10:33:09 -0700
Message-ID: <CAAWBYDD1pzC6=bdzGQtOLNu9XCBWTSgN3CEcQA0f5TmjfuoCNA@mail.gmail.com>
To: Simon Sapin <simon.sapin@kozea.fr>
Cc: www-style@w3.org
On Wed, Sep 26, 2012 at 12:05 AM, Simon Sapin <simon.sapin@kozea.fr> wrote:
> Le 26/09/2012 01:08, Tab Atkins Jr. a écrit :
>> We'd probably also want negations of unknown functions to
>> evaluate as false.  Basically, only an "or" should be able to
>> whitewash away the unrecognized-ness.
>
> Maybe, but why? In terms of boolean logic, having "A" and "not A" both
> evaluate to false is very strange to me. Is there a use case I’m missing?

I agree that it's strange, but you simply *don't know* whether it
should be true or not.  My suggested solution is kinda similar to
NaN-poisoning, where once a NaN is introduced, it remains NaN until
you do something special with it.  This just wipes out the entire
unknown clause.

~TJ
Received on Wednesday, 26 September 2012 17:34:01 GMT

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