On Tue, May 13, 2025 at 7:43 AM Domenic Denicola <dome...@chromium.org> wrote:
> I'm very slightly worried about the cases which we seem to accept, but the > latest on the CSSWG thread suggests we should disallow. Namely, @container > and @page. How sure are you that changing those to be invalid in the > future, to follow the latest CSSWG decisions, will not cause compat > problems? > For @page, I wouldn't be worried at all. It's unlikely someone will start using the feature and rely on a constant sibling-index()/sibling-count() in @page. For @container, I agree that it's safer to be conservative and wait for the resolution, since for @container there are clear use cases and and a more or less obvious behavior in that context. On Tuesday, May 13, 2025 at 6:37:14 AM UTC+9 Mike Taylor wrote: > >> LGTM1 >> On 5/9/25 9:47 AM, Rune Lillesveen wrote: >> >> Contact emails futh...@chromium.org, se...@chromium.org >> >> Explainer >> https://github.com/w3c/csswg-drafts/blob/main/css-values-5/tree-counting-explainer.md >> >> Specification https://drafts.csswg.org/css-values-5/#tree-counting >> >> Design docs >> >> https://github.com/w3c/csswg-drafts/blob/main/css-values-5/tree-counting-explainer.md >> >> Summary >> >> sibling-index() and sibling-count() can be used as integers in CSS >> property values to style elements based on their position among its >> siblings, or the total number of siblings respectively. These functions can >> be used directly as integer values, but more interestingly inside calc() >> expressions. Example: li { margin-left: calc(10px * sibling-index()); } >> >> >> Blink component Blink>CSS >> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3ECSS%22> >> >> TAG review https://github.com/w3ctag/design-reviews/issues/1068 >> >> TAG review status Issues addressed >> >> Risks >> >> >> Interoperability and Compatibility >> >> None >> >> >> *Gecko*: No signal ( >> https://github.com/mozilla/standards-positions/issues/1194) >> >> *WebKit*: No signal ( >> https://github.com/WebKit/standards-positions/issues/471) >> >> *Web developers*: Positive >> >> https://css-tricks.com/how-to-wait-for-the-sibling-count-and-sibling-index-functions/ >> https://chriscoyier.net/2023/11/29/element-indexes/ >> https://kizu.dev/tree-counting-and-random/ >> >> *Other signals*: >> >> WebView application risks >> >> Does this intent deprecate or change behavior of existing APIs, such that >> it has potentially high risk for Android WebView-based applications? >> >> None >> >> >> Debuggability >> >> Basic support out-of-the box. With the value debugger ( >> crbug.com/396080529) shipped, evaluating sibling-index()/sibling-count() >> into a <number> should work out-of-the-box. >> >> >> Will this feature be supported on all six Blink platforms (Windows, Mac, >> Linux, ChromeOS, Android, and Android WebView)? Yes >> >> Is this feature fully tested by web-platform-tests >> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md> >> ? Yes >> >> https://wpt.fyi/results/css/css-values/tree-counting >> >> >> Flag name on about://flags #enable-experimental-web-platform-features >> >> Finch feature name CSSSiblingFunctions >> >> Rollout plan Will ship enabled for all users >> >> Requires code in //chrome? False >> >> Tracking bug https://crbug.com/40282719 >> >> Sample links >> https://codepen.io/argyleink/pen/KwKXPYW >> >> Estimated milestones >> Shipping on desktop 138 >> DevTrial on desktop 133 >> Shipping on Android 138 >> DevTrial on Android 133 >> Shipping on WebView 138 >> >> Anticipated spec changes >> >> >> There is an open issue[1] about what tree counting functions mean outside >> of element contexts. The plan is to handles tree counting functions like >> this for the relevant @-rules when shipping: >> >> >> - @font-face: invalid at parse time >> >> - @font-palette-values: invalid at parse time >> >> - @property: accepted at parse time (the values are strings), but since >> these values are not computationally independent when evaluated, they will >> be dropped as initial values. >> >> - @counter-style: invalid at parse time >> >> - @container: the container is in an element context and tree counting >> functions are evaluated as such >> >> - @page: accepted at parse time and evaluated against the root element >> >> - @media (in query value): invalid at parse time >> >> >> Shipping a different specified behavior for tree counting functions in >> these contexts (to what the issue is resolved to later) should be >> straightforward. >> >> >> [1] https://github.com/w3c/csswg-drafts/issues/10982 >> >> Link to entry on the Chrome Platform Status >> https://chromestatus.com/feature/6225478530367488?gate=6089164107546624 >> >> Links to previous Intent discussions Intent to Prototype: >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/67c70d35.2b0a0220.36af1.0007.GAE%40google.com >> >> This intent message was generated by Chrome Platform Status >> <https://chromestatus.com/>. >> -- >> Rune Lillesveen >> >> -- >> You received this message because you are subscribed to the Google Groups >> "blink-dev" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to blink-dev+unsubscr...@chromium.org. >> To view this discussion visit >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CACuPfeTS2BYBs8yqpNXnJa5tAMwPar4X3jOPtLddMydRX0oEoA%40mail.gmail.com >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CACuPfeTS2BYBs8yqpNXnJa5tAMwPar4X3jOPtLddMydRX0oEoA%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> >> -- Rune Lillesveen -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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