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[css-cascade-6] Do we want to defer some or all of these scope extensions to level 7? #8628
Description
Two of the open issues related to @scope are related to defining extensions to the syntax:
- [cascade-6] Unclear proximity for scoped descendant combinator #8380 attempts to resolve complexity in 'scope proximity combinators' (
>>/~~) - [css-cascade-6] Handle sibling-proximity in @scope #7751 proposes an alternative 'sibling-scope' rule for generating DOM-horizontal scopes
Before we get into discussing and resolving on the details, I just want to note that neither is a core requirement for shipping the existing scope syntax. If we want to defer them to a future spec, the current scope rule can ship uninhibited. To consider each one at a time:
- The scope combinators are a syntax sugar over behavior that can already be achieved using
@scope- but with the added complexity of resolving multiple subjects from a single selector. These may be worth pursuing, but it's not clear that there is a strong need for them - or that the 'semi-de-sugaring' solution proposed will make sense in practice. To me, these feel non-essential. - The sibling-scope proposal has a stronger and more distinct use-case, but not an extremely common one. Since it would reflect the
@scoperule more precisely, it may also be simpler to spec -- but not trivial.
I think both discussions are worth pursuing. I also think both could be deferred in order to ship the central functionality here.
Activity
css-meeting-bot commentedon Mar 22, 2023
The CSS Working Group just discussed
[css-cascade-6] Do we want to defer some or all of these scope extensions to level 7?, and agreed to the following:RESOLVED: The combinator is deferredThe full IRC log of that discussion
<emeyer> miriam: Some tagalong features we can consider; all are useful, question is whther we shoudl be trying to cover them now or defer to next spec level<emeyer> …If we don’t defer them, next on the agenda is a scope sibling feature
<emeyer> …This would be horizontal in the DOM
<emeyer> …A pretty straightforward thing to spec, we think, but it hasn’t been specced
<emeyer> …The other is the scoped proximity combinators
<emeyer> …We have a little less sense when people would use this rather than @scope
<emeyer> …For @scope you’re trying to target several elements in the DOM, and the at-rule does that neatly
<emeyer> …In a single selector, it gets more complex
<TabAtkins> +1 to deferring, they're all nice but none are necessary
<emeyer> …The real question is: defer, or no?
<emeyer> astearns: One concern with deferring is there may be feedback with current-level features that could modify
<emeyer> …If we’re not considering these now, we may miss something
<emeyer> miriam: It’s hard to know if that’s too cautious
<emeyer> …So far neither has caused major changes and will continue to be in our heads, but I dunno
<emeyer> TabAtkins: My estimate is they shouldn’t cause any problems, and should be forward-compatible
<emeyer> astearns: Would it make sense to have a note about things we’ve explicitly deferred?
<bramus> q+
<emeyer> miriam: Since one is partically-specced, it could be opening another spec
<astearns> ack bramus
<fantasai> s/partically/partially/
<emeyer> bramus: I’m okay with deferring combinators due to complexity, but was wondering if we can have sinling scope in level 6
<emeyer> s/sinling/sibling/
<emilio> Implementation-wise they seem a bit trickier than descendant scopes fwiw
<emeyer> astearns: What use case are you concerned about with sibling proximity?
<emilio> Because to change the descendant relationship you need to remove from the DOM but that's not true for siblings
<emeyer> bramus: So authors can style things like start and end dates on a calendar and also styles things between them
<emeyer> miriam: Another example is to style everything between one header and the next header
<astearns> ack fantasai
<emeyer> fantasai: Seems like those are use cases where you don’t need scope proximity effect, you just want the flooring effect, yes?
<emeyer> miriam: I think I’ve seen examples using both
<emeyer> …They achieve the same goal, but at different levels of explicitness and power
<RRSAgent> I have made the request to generate https://www.w3.org/2023/03/22-css-minutes.html fantasai
<emeyer> astearns: Can we resolve on deferring the combinator?
<emeyer> …Proposing deferring 8380 with a note that it was deffered to next level
<emeyer> RESOLVED: The combinator is deferred
[css-cascade-6] Remove (defer) scoped descendant combinator
[css-cascade-6] Remove (defer) scoped descendant combinator (#8718)