2014183 - Create a representation for `@container style()` range queries in the style system

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement)

Description

[Jonathan Kew [:jfkthame]]

The current prototype support for @container style() queries supports custom-property queries like style(--foo), but the StyleFeature type does not support range queries like style(--foo >= 10px) or style(1em < --foo < 2em). As a first step towards this, we need to create a suitable type to represent these queries, before they can be parsed and processed.

My current thought is to convert the StyleFeature struct into an enum with variants for "plain" and "range" queries, where a "plain" query just has a custom property name and (optionally) value, while a "range" query has a sequence of values and operators.

Comment 1

[Emilio Cobos Álvarez [:emilio]]

Would be good to somehow reuse the existing QueryFeatureExpressionKind, which feels pretty similar in that regard: https://searchfox.org/firefox-main/rev/7709f0a26aeb3c39a5fd86e794425530f0d0b528/servo/components/style/queries/feature_expression.rs#159

Comment 2

[Jonathan Kew [:jfkthame]]

Attachment: Bug 2014183 - Create a QueryStyleRange type to represent style-range queries. r=#style

There are separate variants for queries with two values (a < b) vs those
with three values (a < b < c). Another approach would be a single type
where the second operator and third value are Option<>s, but implementing
them as distinct type variants makes for clearer code overall, IMO.

This shares the QueryExpressionValue type with QueryFeatureExpressionKind,
but will be used directly by the condition code rather than embedded in a
QueryFeatureExpression struct, as the feature_type and feature_index fields
there are irrelevant to style-range queries.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/a8ec9e4d2f23
https://hg.mozilla.org/integration/autoland/rev/64e8063a6c25
Create a QueryStyleRange type to represent style-range queries. r=firefox-style-system-reviewers,emilio

Comment 4

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/64e8063a6c25