Support @forward in sass-parser

lib/src/js/parser.dart

@@ -19,6 +19,7 @@ import '../util/string.dart';
 import '../visitor/interface/expression.dart';
 import '../visitor/interface/statement.dart';
 import 'reflection.dart';
+import 'set.dart';
 import 'visitor/expression.dart';
 import 'visitor/statement.dart';
 
@@ -30,13 +31,15 @@ class ParserExports {
       required Function parseIdentifier,
       required Function toCssIdentifier,
       required Function createExpressionVisitor,
-      required Function createStatementVisitor});
+      required Function createStatementVisitor,
+      required Function setToJS  });
 
   external set parse(Function function);
   external set parseIdentifier(Function function);
   external set toCssIdentifier(Function function);
   external set createStatementVisitor(Function function);
   external set createExpressionVisitor(Function function);
+  external set setToJS(Function function);
 }
 
 /// An empty interpolation, used to initialize empty AST entries to modify their
@@ -57,7 +60,8 @@ ParserExports loadParserExports() {
       createExpressionVisitor: allowInterop(
           (JSExpressionVisitorObject inner) => JSExpressionVisitor(inner)),
       createStatementVisitor: allowInterop(
-          (JSStatementVisitorObject inner) => JSStatementVisitor(inner)));
+          (JSStatementVisitorObject inner) => JSStatementVisitor(inner)),
+      setToJS: allowInterop((Set<Object?> set) => new JSSet([...set])));
 }
 
 /// Modifies the prototypes of the Sass AST classes to provide access to JS.

lib/src/js/set.dart

@@ -0,0 +1,10 @@
+// Copyright 2021 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:js/js.dart';
+
+@JS('Set')
+class JSSet {
+  external JSSet(List<Object?> contents);
+}

pkg/sass-parser/lib/index.ts

@@ -72,6 +72,13 @@ export {
   ErrorRuleRaws,
 } from './src/statement/error-rule';
 export {ForRule, ForRuleProps, ForRuleRaws} from './src/statement/for-rule';
+export {
+  ForwardMemberList,
+  ForwardMemberProps,
+  ForwardRule,
+  ForwardRuleProps,
+  ForwardRuleRaws,
+} from './src/statement/forward-rule';
 export {
   GenericAtRule,
   GenericAtRuleProps,

pkg/sass-parser/lib/src/configuration.ts

@@ -13,6 +13,7 @@ import {LazySource} from './lazy-source';
 import {Node} from './node';
 import type * as sassInternal from './sass-internal';
 import * as utils from './utils';
+import {ForwardRule} from './statement/forward-rule';
 import {UseRule} from './statement/use-rule';
 
 /**
@@ -51,7 +52,7 @@ export interface ConfigurationProps {
 export class Configuration extends Node {
   readonly sassType = 'configuration' as const;
   declare raws: ConfigurationRaws;
-  declare parent: UseRule | undefined; // TODO: forward as well
+  declare parent: ForwardRule | UseRule | undefined;
 
   /** The underlying map from variable names to their values. */
   private _variables: Map<string, ConfiguredVariable> = new Map();

pkg/sass-parser/lib/src/sass-internal.ts

@@ -25,6 +25,13 @@ export interface SourceFile {
   getText(start: number, end?: number): string;
 }
 
+export interface DartSet<T> {
+  _type: T;
+
+  // A brand to make this function as a nominal type.
+  _unique: 'DartSet';
+}
+
 // There may be a better way to declare this, but I can't figure it out.
 // eslint-disable-next-line @typescript-eslint/no-namespace
 declare namespace SassInternal {
@@ -37,6 +44,8 @@ declare namespace SassInternal {
 
   function toCssIdentifier(text: string): string;
 
+  function setToJS<T>(set: DartSet<T>): Set<T>;
+
   class StatementVisitor<T> {
     private _fakePropertyToMakeThisAUniqueType1: T;
   }
@@ -105,6 +114,16 @@ declare namespace SassInternal {
     readonly isExclusive: boolean;
   }
 
+  class ForwardRule extends Statement {
+    readonly url: Object;
+    readonly shownMixinsAndFunctions: DartSet<string> | null;
+    readonly shownVariables: DartSet<string> | null;
+    readonly hiddenMixinsAndFunctions: DartSet<string> | null;
+    readonly hiddenVariables: DartSet<string> | null;
+    readonly prefix: string | null;
+    readonly configuration: ConfiguredVariable[];
+  }
+
   class LoudComment extends Statement {
     readonly text: Interpolation;
   }
@@ -247,6 +266,7 @@ export type EachRule = SassInternal.EachRule;
 export type ErrorRule = SassInternal.ErrorRule;
 export type ExtendRule = SassInternal.ExtendRule;
 export type ForRule = SassInternal.ForRule;
+export type ForwardRule = SassInternal.ForwardRule;
 export type LoudComment = SassInternal.LoudComment;
 export type MediaRule = SassInternal.MediaRule;
 export type SilentComment = SassInternal.SilentComment;
@@ -273,6 +293,7 @@ export interface StatementVisitorObject<T> {
   visitErrorRule(node: ErrorRule): T;
   visitExtendRule(node: ExtendRule): T;
   visitForRule(node: ForRule): T;
+  visitForwardRule(node: ForwardRule): T;
   visitLoudComment(node: LoudComment): T;
   visitMediaRule(node: MediaRule): T;
   visitSilentComment(node: SilentComment): T;
@@ -296,3 +317,4 @@ export const parseIdentifier = sassInternal.parseIdentifier;
 export const toCssIdentifier = sassInternal.toCssIdentifier;
 export const createStatementVisitor = sassInternal.createStatementVisitor;
 export const createExpressionVisitor = sassInternal.createExpressionVisitor;
+export const setToJS = sassInternal.setToJS;