Re: [css-values] custom-idents and excluded keywords

On Thu, Mar 17, 2016 at 1:51 AM, Manuel Rego Casasnovas <rego@igalia.com> wrote:
> in the CSS Values spec [1] we could find the following sentence:
> "This generic data type is denoted by <custom-ident>, and represents
>  any valid CSS identifier that would not be misinterpreted as a
>  pre-defined keyword in that property’s value definition."
>
> But a few lines later it says:
> "Specifications using <custom-ident> must specify clearly what other
>  keywords are excluded from <custom-ident>, if any—for example by
>  saying that any pre-defined keywords in that property’s value
>  definition are excluded."
>
> For example in the case of the CSS Grid Layout spec, it's not specified
> which keywords are excluded in the different properties that use
> <custom-ident> (for example the track sizing properties [2]).
> However, in a previous thread [3] Tab said that "minmax", "auto" and
> "subgrid" were not valid <custom-ident>.
>
> The question is if the CSS Grid Layout spec needs to be updated to
> specify the excluded keywords. Or the 2nd sentence above from the CSS
> Values spec needs to be removed/reworded.

Grid needs to be updated.  Previously, Values tried to *automatically*
define that keywords appearing the grammar at the same level were
excluded from <custom-ident>, but that ended up not actually working
in a reasonable way; it implied that different keywords could be
excluded between a longhand and a shorthand, for example.

That section of Grid was just written against the old text, and needs
to be updated to explicitly exclude the handful of keywords that can
appear near it.

~TJ

Received on Friday, 18 March 2016 00:58:58 UTC