feat: implementing the base @scope

src/lib.rs

@@ -21823,6 +21823,29 @@ mod tests {
     );
   }
 
+  #[test]
+  fn test_at_scope() {
+    minify_test(
+      r#"
+      @scope {
+        .foo {
+          display: flex;
+        }
+      }"#,
+      "@scope{.foo{display:flex}}",
+    );
+    minify_test(
+      r#"
+      @scope {
+        :scope {
+          display: flex;
+          color: lightblue;
+        }
+      }"#,
+      "@scope{:scope{color:#add8e6;display:flex}}",
+    );
+  }
+
   #[test]
   fn test_custom_media() {
     custom_media_test(

src/parser.rs

@@ -7,7 +7,9 @@ use crate::rules::container::{ContainerName, ContainerRule};
 use crate::rules::font_palette_values::FontPaletteValuesRule;
 use crate::rules::layer::{LayerBlockRule, LayerStatementRule};
 use crate::rules::property::PropertyRule;
+use crate::rules::scope::ScopeRule;
 use crate::rules::viewport::ViewportRule;
+
 use crate::rules::{
   counter_style::CounterStyleRule,
   custom_media::CustomMediaRule,
@@ -137,6 +139,10 @@ impl<'a, 'o, 'b, 'i, T> TopLevelRuleParser<'a, 'o, 'i, T> {
 pub enum AtRulePrelude<'i, T> {
   /// A @font-face rule prelude.
   FontFace,
+
+  /// A @scope rule prelude.
+  Scope,
+
   /// A @font-feature-values rule prelude, with its FamilyName list.
   FontFeatureValues, //(Vec<FamilyName>),
   /// A @font-palette-values rule prelude, with its name.
@@ -423,6 +429,9 @@ impl<'a, 'o, 'b, 'i, T: crate::traits::AtRuleParser<'i>> AtRuleParser<'i> for Ne
       "font-face" => {
         Ok(AtRulePrelude::FontFace)
       },
+      "scope" => {
+        Ok(AtRulePrelude::Scope)
+      },
       // "font-feature-values" => {
       //     if !cfg!(feature = "gecko") {
       //         // Support for this rule is not fully implemented in Servo yet.
@@ -563,6 +572,10 @@ impl<'a, 'o, 'b, 'i, T: crate::traits::AtRuleParser<'i>> AtRuleParser<'i> for Ne
         rules: self.parse_nested_rules(input)?,
         loc,
       })),
+      AtRulePrelude::Scope => Ok(CssRule::Scope(ScopeRule {
+        rules: self.parse_nested_rules(input)?,
+        loc,
+      })),
       AtRulePrelude::Viewport(vendor_prefix) => {
         Ok(CssRule::Viewport(ViewportRule {
           vendor_prefix,

src/rules/mod.rs

@@ -50,6 +50,7 @@ pub mod namespace;
 pub mod nesting;
 pub mod page;
 pub mod property;
+pub mod scope;
 pub mod style;
 pub mod supports;
 pub mod unknown;
@@ -88,6 +89,7 @@ use media::MediaRule;
 use namespace::NamespaceRule;
 use nesting::NestingRule;
 use page::PageRule;
+use scope::ScopeRule;
 use std::collections::{HashMap, HashSet};
 use style::StyleRule;
 use supports::SupportsRule;
@@ -163,6 +165,8 @@ pub enum CssRule<'i, R = DefaultAtRule> {
   Property(PropertyRule<'i>),
   /// A `@container` rule.
   Container(ContainerRule<'i, R>),
+  /// A `@scope` rule.
+  Scope(ScopeRule<'i, R>),
   /// A placeholder for a rule that was removed.
   Ignored,
   /// An unknown at-rule.
@@ -299,6 +303,10 @@ impl<'i, 'de: 'i, R: serde::Deserialize<'de>> serde::Deserialize<'de> for CssRul
         let rule = ContainerRule::deserialize(deserializer)?;
         Ok(CssRule::Container(rule))
       }
+      "scope" => {
+        let rule = ScopeRule::deserialize(deserializer)?;
+        Ok(CssRule::Scope(rule))
+      }
       "ignored" => Ok(CssRule::Ignored),
       "unknown" => {
         let rule = UnknownAtRule::deserialize(deserializer)?;
@@ -337,6 +345,7 @@ impl<'a, 'i, T: ToCss> ToCss for CssRule<'i, T> {
       CssRule::LayerBlock(layer) => layer.to_css(dest),
       CssRule::Property(property) => property.to_css(dest),
       CssRule::Container(container) => container.to_css(dest),
+      CssRule::Scope(scope) => scope.to_css(dest),
       CssRule::Unknown(unknown) => unknown.to_css(dest),
       CssRule::Custom(rule) => rule.to_css(dest).map_err(|_| PrinterError {
         kind: PrinterErrorKind::FmtError,
@@ -641,6 +650,7 @@ impl<'i, T> CssRuleList<'i, T> {
             continue;
           }
         }
+        CssRule::Scope(scope) => scope.minify(context)?,
         CssRule::Nesting(nesting) => {
           if nesting.minify(context, parent_is_unused)? {
             continue;

src/rules/scope.rs

@@ -0,0 +1,54 @@
+//! The `@scope` rule.
+
+use super::Location;
+use super::{CssRuleList, MinifyContext};
+use crate::error::{MinifyError, PrinterError};
+use crate::parser::DefaultAtRule;
+use crate::printer::Printer;
+use crate::traits::ToCss;
+#[cfg(feature = "visitor")]
+use crate::visitor::Visit;
+
+/// A [@scope](https://drafts.csswg.org/css-cascade-6/#scope-atrule) rule.
+///
+/// @scope (<scope-start>) [to (<scope-end>)]? {
+///  <stylesheet>
+/// }
+#[derive(Debug, PartialEq, Clone)]
+#[cfg_attr(feature = "visitor", derive(Visit))]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "jsonschema", derive(schemars::JsonSchema))]
+pub struct ScopeRule<'i, R = DefaultAtRule> {
+  // TODO: support (<scope-start>) [to (<scope-end>)]?
+  /// Nested rules within the `@scope` rule.
+  #[cfg_attr(feature = "serde", serde(borrow))]
+  pub rules: CssRuleList<'i, R>,
+  /// The location of the rule in the source file.
+  #[cfg_attr(feature = "visitor", skip_visit)]
+  pub loc: Location,
+}
+
+impl<'i, T> ScopeRule<'i, T> {
+  pub(crate) fn minify(&mut self, context: &mut MinifyContext<'_, 'i>) -> Result<(), MinifyError> {
+    self.rules.minify(context, false)
+  }
+}
+
+impl<'i, T: ToCss> ToCss for ScopeRule<'i, T> {
+  fn to_css<W>(&self, dest: &mut Printer<W>) -> Result<(), PrinterError>
+  where
+    W: std::fmt::Write,
+  {
+    #[cfg(feature = "sourcemap")]
+    dest.add_mapping(self.loc);
+    dest.write_str("@scope")?;
+    dest.whitespace()?;
+    dest.write_char('{')?;
+    dest.indent();
+    dest.newline()?;
+    self.rules.to_css(dest)?;
+    dest.dedent();
+    dest.newline()?;
+    dest.write_char('}')
+  }
+}