Disposition of comments for Media Queries CR

Parsing media queries

In HTML4 it was pretty clear. You first split on the "," and then remove all characters after the first non ASCII-letter, hyhen or digit. The resulting values are the media specified.

For Media Queries it's not clear what rules you have to follow when the media query given (after splitting on ",") doesn't match the syntax. It's important to know this for the CSSOM MediaList interface for instance.

After reading the reply to comment #8, Anne writes: Ah ok, I guess that sort of solves it. It does mean though that "not all and (foobar)" would apply. Is that desirable? I was thinking that such a media query should perhaps simply be ignored completely so we don't have to worry about how to represent it in the DOM either. That seems also more in line with error handling in CSS.

Proposed changes:

   http://www.w3.org/TR/css3-mediaqueries/#device-aspect-ratio

   # In this specification, aspect ratio is defined as the number of
   # horizontal pixels over the number of vertical pixels.

   change to

   | In this specification, aspect ratio is defined as the horizontal
   | length of the device's display divided by its vertical length.


   http://www.w3.org/TR/css3-mediaqueries/#resolution

   # The 'resolution' media feature describes the resolution of the
   # output device, i.e. the density of the pixels.

   Add

   | When querying devices with non-square pixels, in 'min-resolution'
   | queries the least-dense dimension must be compared to the specified
   | value and in 'max-resolution' queries the most-dense dimensions must
   | be compared instead. A fixed 'resolution' query never matches a device
   | with non-square pixels.

   (Alternatively we could allow two values to query each dimension
   independently, but I don't think this is useful.)

'not' and unknown media types:

Section 3 says: "The presence of the keyword 'not' at the beginning of the
query negates the results."  Section 4 says: "Media queries involving
unknown media types are always false".

When I read that, the word 'always' led me to wonder whether or not unknown
media types trump the section 3 definition of 'not'.  I suggest the
following clarifications:

1) remove the word "always" from the section 4 statement
2) Add an example showing that the following media query is true:

     @media not 3d-glasses { ... }

it'd be nice if we defined the lack of a media query string to mean "all"

Parsing is not well defined in terms of whitespace and error handling.

grid doesn't apply to all media

http://dev.w3.org/csswg/css3-mediaqueries/#media1 says:
  # For a media feature feature, (feature) will evaluate to true if
  # (feature:x) will evaluate to true for a value x other than zero.
 
Does this mean:
 
  (a) (width) is always true, even if the viewport width is zero,
  because "0px" is a value other than zero, or:
 
  (b) (width) is false when the viewport width is zero because "0px"
  and "0" are both not "other than zero"?
 
I'd also note that because specified widths cannot be negative,
(max-width) currently behaves the same as (width), whereas
(min-width) is always true.  Is that really intended?

After reading http://dev.w3.org/csswg/css3-mediaqueries/#grid it's
not clear to me whether the queries "(grid: -1)" or "(grid: 2)"
should be parse errors or should always be false.  It should be
clear.