[css-counter-styles] additive-symbols of the same weight #1220
Description
https://drafts.csswg.org/css-counter-styles/#additive-tuple
Each entry in the additive-symbols descriptor’s value defines an additive tuple, which consists of a counter symbol and a non-negative integer weight. Each weight must be a non-negative integer, and the additive tuples must be specified in order of descending weight; otherwise, the @counter-style is invalid and must be ignored.
- This doesn’t say what to do with multiple additive tuples of the same declaration have the same weight, which doesn’t make sense in the algorithm. Since the syntax requires tuples to be in order, it could also reject that case. Firefox does this. The spec should make this explicit.
- This bit of spec says that negative integers or out of order tuples make the entire rule invalid, not just the descriptor declaration. This is highly unusual, compared to other descriptors/properties in
@counter-styleor other types of rules. This makes a difference because there could be multipleadditive-symbolsdeclarations, where an invalid latter one would could the earlier one to be used. This can be useful as a fallback mechanism for using a new feature not implemented everywhere. I think “the @counter-style is invalid” here should be changed to “the declaration is invalid”. Firefox only makes the declaration invalid.
CC @upsuper