Description
The current definition of the <family-name> type is:
The name of a font family of choice such as Helvetica or Verdana in the previous example.
And the <feature-index> and <feature-value-name> types are currently defined like this:
… the @font-feature-values rule is used to define values for a specific font family or set of families that associate a font-specific numeric
<feature-index>with a custom<feature-value-name>, which is then used in this property to select specific alternates
This is somewhat vague, as there are no references to the related syntax definitions.
The definitions should be changed to use the syntax from the CSS Syntax Module.
I.e. they may look like this:
@font-face = @font-face { <declaration-list> }
where <declaration-list> can only contain the @font-face descriptors.
and
@font-feature-values = @font-feature-values <family-name># { <rule-list> }
<family-name> = <string> | <custom-ident>+
<feature-value-block> = <feature-type> { <declaration-list> }
<feature-type> = @stylistic | @historical-forms | @styleset | @character-variant | @swash | @ornaments | @annotation
<feature-value> = <integer>+
where <rule-list> can only contain <feature-value-block> rules, <feature-type> takes all font specific property names of font-variant-alternates prefixed with '@', <declaration-list> can only contain feature value definition properties holding <feature-value> values and the <integer> values in <feature-value> denote the feature indices.
The references to these syntax definitions should then link to them.
Sebastian