- From: Tab Atkins Jr. <jackalmage@gmail.com>
- Date: Wed, 22 Apr 2015 12:32:23 -0700
- To: Simon Sapin <simon.sapin@exyr.org>
- Cc: Florian Rivoal <florian@rivoal.net>, www-style list <www-style@w3.org>
On Wed, Apr 22, 2015 at 9:45 AM, Simon Sapin <simon.sapin@exyr.org> wrote: > Another option that came up in today’s call is tri-state logic: > > Intermediate terms of a media query, in addition to evaluating to either > true or false, could evaluate to "maybe" with the following rules: > > * <general-enclosed> evaluates to maybe > * `not maybe` evaluates to maybe > * `maybe and X` evaluates to maybe > * `maybe or X` evaluates to X > * <media-query> evaluating to maybe is the same as evaluating to false. > > The point of all this is that for Y that evaluates to true and Z that has > evaluates to true, me might want `Y and Z` to evaluate to true. You got that last part confused. What we want is for "Y or Z" to be true if Y or Z is true, regardless of what the other one is. In particular, we don't want a <general-enclosed> on one side to mess that up, because it's irrelevant. Your truth table is mostly correct, but I think "maybe AND false" should be false. In particular, we should be implementing the Kleene 3-value logic: http://en.wikipedia.org/wiki/Three-valued_logic#Kleene_and_Priest_logics ~TJ
Received on Wednesday, 22 April 2015 19:33:10 UTC