[css-cascade-6] change lower boundary keyword for @scope to "until"

[grncdr]

The current proposed syntax for @scope rules with a lower bound is:

@scope ([data-scope='main-component']) to ([data-scope]) {
  p { color: red; }

  /* only the outer section is part of the outer scope */
  section { background: snow; }
}

https://drafts.csswg.org/css-cascade-6/#at-ruledef-scope

A smaller change that was proposed in #6577 but did not get explored further (as far as I know) was using the keyword until instead of to for an exclusive lower bound. I'd like to request that "until" be considered as a more suitable keyword.

• it clearly communicates that the lower bound is exclusive (which is great, I 1000% agree with that resolution).
• it is less likely to be misread as the second selector being the container.

The above might require a bit of explanation: when discussing scope in other programming contexts (e.g. JavaScript) the statement "X is scoped to Y" designates Y as the container of X. A rule like @scope (.x) to (.y) does not have a similar meaning, despite looking superficially identical.

When searching for examples I found this article by Raymond Chen on this exact subject. While his article is about Microsoft, the usage is common across the internet.

There are many more examples on MDN: https://developer.mozilla.org/en-US/search?q=%22scoped%20to%22

---

I recognize this issue is a bit "bikesheddy" but I think it's a big improvement in readability for what is going to be a high-profile feature.

[grncdr]

A comment with the same idea from last September: https://css-tricks.com/early-days-for-css-scoping/#comment-1782132

[mirisuzanne]

Agenda+ to get group feedback on this. I don't have a strong leaning one way or the other.

[DarkWiiPlayer]

I agree that, intuitively, to makes me think the lower boundary is included. until would probably avoid some confusion there.

[css-meeting-bot]

The CSS Working Group just discussed [css-cascade-6] change lower boundary keyword for @scope to "until", and agreed to the following:

• RESOLVED: close the issue as no-change

The full IRC log of that discussion

<fremy> miriam: this is a bikeshedding issue open for a while
<fremy> miriam: the concern is that "scoped to" usually means "it's inside the scope"
<fremy> miriam: so it might be confusing to also use "to" to say that the scope goes "from...to"
<fantasai> wfm
<fremy> miriam: I have no strong opinion on it
<bramus> q+
<fremy> fremy: wfm too
<astearns> ack bramus
<TabAtkins> q+
<fremy> bramus: no hard feelings, but "to" sounded better to me, because as a non-native English speaker "until" is not very frequent
<fremy> bramus: this might also be related to the next issue
<astearns> ack TabAtkins
<fremy> bramus: if we choose to include the boundaries, "to" might be better
<fremy> TabAtkins: there is no clear English word that indicates exclusivity or inclusivity with clarity
<fremy> TabAtkins: so I don't think the choice of term is not that important
<fremy> TabAtkins: and therefore believe going with the shortest one makes the most sense
<astearns> ack fantasai
<fremy> fantasai: while I agree with TabAtkins that the inclusivity is not clear in either wording
<TabAtkins> "range from 0 to 3" can easily mean [0,1,2,3] or [0,1,2] depending on context. Even sometimes [1,2].
<fremy> fantasai: that said, I can understand the other argument
<fremy> fantasai: but maybe we could use something else than a word, like the > sign?
<bramus> q+
<TabAtkins> I think we should avoid `>` next to selectors, due its context-specific meaning there.
<fremy> fantasai: that would avoid the problems with the choice of an English word
<astearns> ack bramus
<fremy> bramus: the > sign is also a combinator
<fremy> miriam: but scoping extends in the same direction as the combinator
<fremy> miriam: so not a problem for me, though I still like "to" a bit better I guess
<fantasai> s/other argument/other argument about how "scoped to the X element" means using X as the scoping root/
<fremy> astearns: there doesn't seem to be passionate comments for any of the comments
<fremy> astearns: so maybe we should just leave things as they are, for lack of a huge reason to change
<bramus> +1
<fremy> astearns: "to" is easier to spell, and not any more precise
<fantasai> "thru", to use Tab's spelling :p
<fremy> miriam: ok, let's propose to close no change
<fremy> astearns: yes, and if someone has a stronger argument or more data etc we could revisit
<TabAtkins> The only clear range-based english keywords I've ever really seen were in Lisp's LOOP macro - "0 to " was inclusive, "0 below 3" was exclusive.
<fremy> fantasai: like a more compelling rationale or something
<fremy> astearns: any objection?
<fremy> RESOLVED: close the issue as no-change

[fantasai]

The other option that came up in the discussion was to use some symbol instead of a keyword, e.g. ">":

@scope ([data-scope='main-component']) > ([data-scope]) {
  p { color: red; }
}

[mirisuzanne]

Closing for now - but it can always be re-opened if someone wants to make a stronger case for one of the alternatives.