[css-backgrounds] Incorrect value dfn for border-color and background-clip

[tidoust]

The border-color definition seems to be using parentheses for grouping instead of brackets as described in Component value combinators. Correct value should be [<color>{1,4}]#.

Also, the "Value" header link is wrong, it should target https://drafts.csswg.org/css-backgrounds-4/#values as in all other property definition tables.

Similarly, I would expect to be able to parse the new values of background-clip using the usual Value Definition Syntax. For that to be possible, value should be text | border, and not text, border.

[tidoust]

I don't want to make things unnecessarily complicated but something I had overlooked in this case is that the definition of background-clip is <box>#, and "New value" actually extends <box> (defined as border-box | padding-box | content-box), not the property itself.

In other words, the spec probably wants the final property to be defined as [ border-box | padding-box | content-box | text | border ] # and not as <box># | text | border, the latter being what a strict application of the rules would yield.

[tabatkins]

Ah, indeed.

[tabatkins]

Well, hm. I don't want to repeat the <box> values. I think what I want to do is redefine the property entirely to <bg-clip-value>#, and then define that to be <box> | border | text.