[css-values-5] Why is sibling-count() self-including?

[nt1m]

I just discovered today that sibling-count() is self-including today:

The sibling-count() functional notation represents, as an <integer>, the total number of child elements in the parent of the element on which the notation is used.

I guess this might be an english language bias, but when people ask "how many siblings do you have?", you usually don't include yourself.

There might be a reason for this choice (perhaps simply avoiding 0 which is problematic in division and other calculations) but I couldn't find a previous issue about this. I'd personally find it surprising the first time I would use this function, but I could live with it.

[nt1m]

cc @tabatkins @argyleink @weinig

[Loirooriol]

See #4559 (comment), #4559 (comment)

[yisibl]

I guess this might be an english language bias, but when people ask "how many siblings do you have?", you usually don't include yourself.

In the Chinese context, it usually includes myself.

[lilles]

@nt1m Did the previous discussions linked to by @Loirooriol cover your concerns, or do you want this issue to be further discussed?

[tabatkins]

It's self-including because the use-cases for it all involve the total child counts. Almost any example that wants to style something based on how many children are in an element wants to know the total number, like calc(100% / sibling-count()) or something. Counting the number of children excluding the element itself is a much more niche use, and in the rare cases it is what you want, can be done with a simple - 1 in the calc().

I understand that the name sibling-count() somewhat leans toward the "excluding the element itself" meaning, but there's no better English word to use. We originally thought to name these functions similar to the selector functions, but "children" was more confusing, since it implied counting or indexing the element's children, not the set of children the element was part of. We switched to "sibling" for clarity, knowing this sort of confusion was possible, and judged it worthwhile.

(Even in English, it's a little ambiguous - if you're asked "how many siblings do you have?" I sometimes say "there's 3 of us, me and my two brothers", because people are usually actually wanting to ask how many children my parents have, but are talking to me and so are compelled to phrase the question with me as the subject.)

[nt1m]

Yeah that makes sense, parent-children-count() could be a possibility but I don't think it's worth the verbosity