[css-gaps-1] Computed value of [column|row]-rule-width with none|hidden style and lists of values

[kbabbitt]

Per CSS Multicol 1, if column-rule-style is none or hidden, then the computed value of column-rule-width will be 0.

Gaps 1 extends the definitions of the column-rule-* properties to allow for lists of values. It also seeks to preserve the existing behavior noted above for backwards compatibility. But in what cases should the backward compatibility behavior apply? I can see a couple of reasonable possibilities:

1. If column-rule-style contains exactly one value and that value is none or hidden, then the computed value of column-rule-width is 0.
2. If column-rule-style contains nothing other than none, hidden, or repeaters containing nothing other than none or hidden, then the computed value of column-rule-width is 0.

My inclination is towards 1. Does the WG agree? Any options I might have missed?

[Loirooriol]

I'm assuming that repeat() is preserved at computed-value time, so it's not possible to just set to zero the width at the same index, right?

[kbabbitt]

I'm assuming that repeat() is preserved at computed-value time, so it's not possible to just set to zero the width at the same index, right?

Yes, and a similar consideration is that lists for different properties can repeat and have different lengths. For example:

column-rule-style: solid dashed none;
column-rule-width: 1px 2px;

Would give, in order from left to right: 1px solid, 2px dashed, (1px) none, 2px solid, 1px dashed, (2px) none.