Re: [css3-fonts] @font-feature-values syntax

On Wed, Sep 26, 2012 at 5:50 AM, fantasai <fantasai.lists@inkedblade.net>wrote:

> During discussions about the @font-feature-values rule syntax, there
> were several variations that came up. I wanted to bring up one of the
> other variations for comparison and hear what other people think about
> their relative merits.
>
> The @font-feature-values rule is used to bind a name to a font feature
> code in the context of a particular font. If multiple name bindings for
> the same feature type are declared, they all take effect, except when
> reusing the same name the last declared value wins.
>
> Variation A is the one in the draft. It looks like this:
>
>   @font-feature-values <font-name> {
>      @<feature-type> <ident> <value>, <ident> <value, ...;
>      ...
>   }
>
>   Here's an example from the draft:
>   @font-feature-values Mars Serif {
>     @styleset alt-g 1,
>               curly-quotes 3,
>               code 4 5;
>     @styleset dumb 25;
>     @swash    swishy 3 5;
>   }
>
> Variation B uses a syntax similar to standard rule sets:
>
>   @font-feature-values <font-name> {
>      <feature-type> {
>        <ident>: <value>;
>        <ident>: <value>;
>        ...
>      }
>      ...
>   }
>
>   Here's the equivalent example in this syntax:
>
>   @font-feature-values Mars Serif {
>     styleset { alt-g: 1;
>                curly-quotes: 3;
>                code: 4 5; }
>     styleset { dumb: 25; }
>     swash { swishy: 3 5; }
>   }
>
> The primary benefit of Variation A is that it's slightly more compact,
> since it doesn't use curly braces.
>
> The primary benefit of Variation B is that the cascading behavior of
> the name bindings behaves exactly as you would expect from the syntax:
> exactly as if the feature type were an element type selector, and the
> name declarations were property declarations.


I vote for variation B. Variation A looks odd to me and is more likely to
confuse authors IMO. Variation B is closer to the current syntax of other
@rules, except that what looks like selectors in B select a feature type,
but that's OK.