Parse selectors in the sass-parser package

lib/src/ast/sass.dart

@@ -29,6 +29,21 @@ export 'sass/expression/variable.dart';
 export 'sass/import.dart';
 export 'sass/import/dynamic.dart';
 export 'sass/import/static.dart';
+export 'sass/interpolated_selector.dart';
+export 'sass/interpolated_selector/attribute.dart';
+export 'sass/interpolated_selector/class.dart';
+export 'sass/interpolated_selector/complex_component.dart';
+export 'sass/interpolated_selector/complex.dart';
+export 'sass/interpolated_selector/compound.dart';
+export 'sass/interpolated_selector/id.dart';
+export 'sass/interpolated_selector/list.dart';
+export 'sass/interpolated_selector/parent.dart';
+export 'sass/interpolated_selector/placeholder.dart';
+export 'sass/interpolated_selector/pseudo.dart';
+export 'sass/interpolated_selector/qualified_name.dart';
+export 'sass/interpolated_selector/simple.dart';
+export 'sass/interpolated_selector/type.dart';
+export 'sass/interpolated_selector/universal.dart';
 export 'sass/interpolation.dart';
 export 'sass/node.dart';
 export 'sass/parameter.dart';

lib/src/ast/sass/interpolated_selector.dart

@@ -0,0 +1,20 @@
+// Copyright 2025 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import '../../visitor/interface/interpolated_selector.dart';
+import 'node.dart';
+
+// Note: this has to be a concrete class so we can expose its accept() function
+// to the JS parser.
+
+/// A simple selector before interoplation is resolved.
+///
+/// Unlike [Selector], this is parsed during the initial stylesheet parse
+/// when `parseSelectors: true` is passed to [Stylesheet.parse].
+///
+/// {@category AST}
+abstract base class InterpolatedSelector implements SassNode {
+  /// Calls the appropriate visit method on [visitor].
+  T accept<T>(InterpolatedSelectorVisitor<T> visitor);
+}

lib/src/ast/sass/interpolated_selector/attribute.dart

@@ -0,0 +1,71 @@
+// Copyright 2025 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:source_span/source_span.dart';
+
+import '../../../visitor/interface/interpolated_selector.dart';
+import '../../css/value.dart';
+import '../../sass/interpolation.dart';
+import '../../selector.dart';
+import 'qualified_name.dart';
+import 'simple.dart';
+
+/// An attribute selector.
+///
+/// Unlike [AttributeSelector], this is parsed during the initial stylesheet
+/// parse when `parseSelectors: true` is passed to [Stylesheet.parse].
+///
+/// {@category AST}
+final class InterpolatedAttributeSelector extends InterpolatedSimpleSelector {
+  /// The name of the attribute being selected for.
+  final InterpolatedQualifiedName name;
+
+  /// The operator that defines the semantics of [value].
+  ///
+  /// This is `null` if and only if [value] is `null`.
+  final CssValue<AttributeOperator>? op;
+
+  /// An assertion about the value of [name].
+  ///
+  /// This is `null` if and only if [op] is `null`.
+  final Interpolation? value;
+
+  /// The modifier which indicates how the attribute selector should be
+  /// processed.
+  ///
+  /// If [op] is `null`, this is always `null` as well.
+  final Interpolation? modifier;
+
+  final FileSpan span;
+
+  /// Creates an attribute selector that matches any element with a property of
+  /// the given name.
+  InterpolatedAttributeSelector(this.name, this.span)
+      : op = null,
+        value = null,
+        modifier = null;
+
+  /// Creates an attribute selector that matches an element with a property
+  /// named [name], whose value matches [value] based on the semantics of [op].
+  InterpolatedAttributeSelector.withOperator(
+    this.name,
+    this.op,
+    this.value,
+    this.span, {
+    this.modifier,
+  });
+
+  /// Calls the appropriate visit method on [visitor].
+  T accept<T>(InterpolatedSelectorVisitor<T> visitor) =>
+      visitor.visitAttributeSelector(this);
+
+  String toString() {
+    var result = '[$name';
+    if (op != null) {
+      result += '$op$value';
+      if (modifier != null) result += ' $modifier';
+    }
+    return result;
+  }
+}

lib/src/ast/sass/interpolated_selector/class.dart

@@ -0,0 +1,32 @@
+// Copyright 2025 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:source_span/source_span.dart';
+
+import '../../../visitor/interface/interpolated_selector.dart';
+import '../../sass/interpolation.dart';
+import '../../selector.dart';
+import 'simple.dart';
+
+/// A class selector.
+///
+/// Unlike [ClassSelector], this is parsed during the initial stylesheet parse
+/// when `parseSelectors: true` is passed to [Stylesheet.parse].
+///
+/// {@category AST}
+final class InterpolatedClassSelector extends InterpolatedSimpleSelector {
+  /// The class name this selects for.
+  final Interpolation name;
+
+  FileSpan get span =>
+      name.span.file.span(name.span.start.offset - 1, name.span.end.offset);
+
+  InterpolatedClassSelector(this.name);
+
+  /// Calls the appropriate visit method on [visitor].
+  T accept<T>(InterpolatedSelectorVisitor<T> visitor) =>
+      visitor.visitClassSelector(this);
+
+  String toString() => '.$name';
+}

lib/src/ast/sass/interpolated_selector/complex.dart

@@ -0,0 +1,48 @@
+// Copyright 2025 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:source_span/source_span.dart';
+
+import '../../../visitor/interface/interpolated_selector.dart';
+import '../../css/value.dart';
+import '../../selector.dart';
+import '../interpolated_selector.dart';
+import 'complex_component.dart';
+
+/// A complex selector before interoplation is resolved.
+///
+/// Unlike [ComplexSelector], this is parsed during the initial stylesheet parse
+/// when `parseSelectors: true` is passed to [Stylesheet.parse].
+///
+/// {@category AST}
+final class InterpolatedComplexSelector extends InterpolatedSelector {
+  /// This selector's leading combinator.
+  ///
+  /// If this is null, that indicates that it has no leading combinator. It's only null if
+  final CssValue<Combinator>? leadingCombinator;
+
+  /// The components of this selector.
+  ///
+  /// This is only empty if [leadingCombinators] is not null.
+  final List<InterpolatedComplexSelectorComponent> components;
+
+  final FileSpan span;
+
+  InterpolatedComplexSelector(
+      Iterable<InterpolatedComplexSelectorComponent> components, this.span,
+      {this.leadingCombinator})
+      : components = List.unmodifiable(components) {
+    if (leadingCombinator == null && this.components.isEmpty) {
+      throw ArgumentError(
+        "components may not be empty if leadingCombinator is null.",
+      );
+    }
+  }
+
+  /// Calls the appropriate visit method on [visitor].
+  T accept<T>(InterpolatedSelectorVisitor<T> visitor) =>
+      visitor.visitComplexSelector(this);
+
+  String toString() => components.join(' ');
+}

lib/src/ast/sass/interpolated_selector/complex_component.dart

@@ -0,0 +1,38 @@
+// Copyright 2025 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:source_span/source_span.dart';
+
+import '../../css/value.dart';
+import '../../selector.dart';
+import '../node.dart';
+import 'compound.dart';
+
+/// A component of a [InterpolatedComplexSelector].
+///
+/// Unlike [ComplexSelectorComponent], this is parsed during the initial
+/// stylesheet parse when `parseSelectors: true` is passed to
+/// [Stylesheet.parse].
+///
+/// {@category AST}
+final class InterpolatedComplexSelectorComponent implements SassNode {
+  /// This component's compound selector.
+  final InterpolatedCompoundSelector selector;
+
+  /// This selector's combinator.
+  ///
+  /// If this is null, that indicates that it has an implicit descendent
+  /// combinator.
+  final CssValue<Combinator>? combinator;
+
+  final FileSpan span;
+
+  InterpolatedComplexSelectorComponent(this.selector, this.span,
+      {this.combinator});
+
+  String toString() => switch (combinator) {
+        var combinator? => '$selector $combinator',
+        _ => selector.toString()
+      };
+}

lib/src/ast/sass/interpolated_selector/compound.dart

@@ -0,0 +1,38 @@
+// Copyright 2025 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:source_span/source_span.dart';
+
+import '../../../visitor/interface/interpolated_selector.dart';
+import '../../selector.dart';
+import '../interpolated_selector.dart';
+import 'simple.dart';
+
+/// A compound selector before interoplation is resolved.
+///
+/// Unlike [CompoundSelector], this is parsed during the initial stylesheet parse
+/// when `parseSelectors: true` is passed to [Stylesheet.parse].
+///
+/// {@category AST}
+final class InterpolatedCompoundSelector extends InterpolatedSelector {
+  /// The components of this selector.
+  final List<InterpolatedSimpleSelector> components;
+
+  FileSpan get span => components.length == 1
+      ? components.first.span
+      : components.first.span.expand(components.last.span);
+
+  InterpolatedCompoundSelector(Iterable<InterpolatedSimpleSelector> components)
+      : components = List.unmodifiable(components) {
+    if (this.components.isEmpty) {
+      throw ArgumentError("components may not be empty.");
+    }
+  }
+
+  /// Calls the appropriate visit method on [visitor].
+  T accept<T>(InterpolatedSelectorVisitor<T> visitor) =>
+      visitor.visitCompoundSelector(this);
+
+  String toString() => components.join('');
+}

lib/src/ast/sass/interpolated_selector/id.dart

@@ -0,0 +1,32 @@
+// Copyright 2025 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:source_span/source_span.dart';
+
+import '../../../visitor/interface/interpolated_selector.dart';
+import '../../sass/interpolation.dart';
+import '../../selector.dart';
+import 'simple.dart';
+
+/// An ID selector.
+///
+/// Unlike [IDSelector], this is parsed during the initial stylesheet parse when
+/// `parseSelectors: true` is passed to [Stylesheet.parse].
+///
+/// {@category AST}
+final class InterpolatedIDSelector extends InterpolatedSimpleSelector {
+  /// The id name this selects for.
+  final Interpolation name;
+
+  FileSpan get span =>
+      name.span.file.span(name.span.start.offset - 1, name.span.end.offset);
+
+  InterpolatedIDSelector(this.name);
+
+  /// Calls the appropriate visit method on [visitor].
+  T accept<T>(InterpolatedSelectorVisitor<T> visitor) =>
+      visitor.visitIDSelector(this);
+
+  String toString() => '#$name';
+}

lib/src/ast/sass/interpolated_selector/list.dart

@@ -0,0 +1,39 @@
+// Copyright 2025 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:source_span/source_span.dart';
+
+import '../../../visitor/interface/interpolated_selector.dart';
+import '../interpolated_selector.dart';
+import 'complex.dart';
+
+/// A selector list before interoplation is resolved.
+///
+/// Unlike [SelectorList], this is parsed during the initial stylesheet parse
+/// when `parseSelectors: true` is passed to [Stylesheet.parse].
+///
+/// {@category AST}
+final class InterpolatedSelectorList extends InterpolatedSelector {
+  /// The components of this selector.
+  ///
+  /// This is never empty.
+  final List<InterpolatedComplexSelector> components;
+
+  FileSpan get span => components.length == 1
+      ? components.first.span
+      : components.first.span.expand(components.last.span);
+
+  InterpolatedSelectorList(Iterable<InterpolatedComplexSelector> components)
+      : components = List.unmodifiable(components) {
+    if (this.components.isEmpty) {
+      throw ArgumentError("components may not be empty.");
+    }
+  }
+
+  /// Calls the appropriate visit method on [visitor].
+  T accept<T>(InterpolatedSelectorVisitor<T> visitor) =>
+      visitor.visitSelectorList(this);
+
+  String toString() => components.join(', ');
+}

lib/src/ast/sass/interpolated_selector/parent.dart

@@ -0,0 +1,32 @@
+// Copyright 2025 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:source_span/source_span.dart';
+
+import '../../../visitor/interface/interpolated_selector.dart';
+import '../../sass/interpolation.dart';
+import '../../selector.dart';
+import 'simple.dart';
+
+/// A parent selector.
+///
+/// Unlike [ParentSelector], this is parsed during the initial stylesheet parse
+/// when `parseSelectors: true` is passed to [Stylesheet.parse].
+///
+/// {@category AST}
+final class InterpolatedParentSelector extends InterpolatedSimpleSelector {
+  /// The suffix that will be added to the parent selector after it's been
+  /// resolved.
+  final Interpolation? suffix;
+
+  final FileSpan span;
+
+  InterpolatedParentSelector(this.span, {this.suffix});
+
+  /// Calls the appropriate visit method on [visitor].
+  T accept<T>(InterpolatedSelectorVisitor<T> visitor) =>
+      visitor.visitParentSelector(this);
+
+  String toString() => switch (suffix) { var suffix? => '&$suffix', _ => '&' };
+}