[interop] Add Support for Anonymous Declarations (#434)

This adds support for generating declarations for anonymous declarations, such as anonymous objects, unions, closures and constructor types.

This also adds support for nullable types (types unioned with undefined and/or null).

A hashing function is used for consistently hashing string objects, which is used for hashing identifiers for anonymous unions, objects and more, as well as comparing such names to allow reusing of such types.

* wip: union types

* wip: completed anonymous unions

* implemented JS Tuple

* completed nullability support for `undefined` and `null`

* wip: object decl

* implemented anonymous objects

* added support for closures and constructors

* wip: type hierarchy

* implemented sub type deduction

* added type generics to union types

* changed `.reduce` to `.fold`

* resolved newline and license headers

* isNullable updates and renamed `DeclarationAssociatedType`

* updated algorithm to use LCA via Topological Ordering

* resolved some more comments

* rm hasher_test

* resolved some more comments

* refactored tuple generation (common types) and more

* added LCA test

* removed stray prints

* added doc support and resolved merge

* updated documentation formatting using formatting.dart

Author: nikeokoronkwo

web_generator/analysis_options.yaml

@@ -6,6 +6,8 @@ analyzer:
     strict-casts: true
     strict-inference: true
     strict-raw-types: true
+  errors: 
+    comment_references: ignore
 
 linter:
   rules:

web_generator/lib/src/ast/base.dart

@@ -45,7 +45,6 @@ class ASTOptions {
 }
 
 sealed class Node {
-  String? get name;
   abstract final ID id;
   String? get dartName;
 
@@ -55,7 +54,6 @@ sealed class Node {
 }
 
 abstract class Declaration extends Node {
-  @override
   String get name;
 
   @override
@@ -66,11 +64,19 @@ abstract class NamedDeclaration extends Declaration {
   @override
   abstract String name;
 
-  abstract Documentation? documentation;
-
-  ReferredType asReferredType([List<Type>? typeArgs, String? url]) =>
+  ReferredType asReferredType(
+          [List<Type>? typeArgs, bool isNullable = false, String? url]) =>
       ReferredType(
-          name: name, declaration: this, typeParams: typeArgs ?? [], url: url);
+          name: name,
+          declaration: this,
+          typeParams: typeArgs ?? [],
+          url: url,
+          isNullable: isNullable);
+}
+
+abstract interface class DocumentedDeclaration {
+  /// The documentation associated with the given declaration
+  abstract Documentation? documentation;
 }
 
 abstract interface class ExportableDeclaration extends Declaration {
@@ -88,8 +94,20 @@ abstract class Type extends Node {
   @override
   String? dartName;
 
+  /// Whether the given type is nullable or not
+  /// (unioned with `undefined` or `null`)
+  abstract bool isNullable;
+
   @override
   Reference emit([covariant TypeOptions? options]);
+
+  @override
+  bool operator ==(Object other) {
+    return other is Type && id == other.id;
+  }
+
+  @override
+  int get hashCode => Object.hashAll([id]);
 }
 
 abstract class FieldDeclaration extends NamedDeclaration {
@@ -106,6 +124,12 @@ abstract class CallableDeclaration extends NamedDeclaration {
 
 enum DeclScope { private, protected, public }
 
+abstract class DeclarationType<T extends Declaration> extends Type {
+  T get declaration;
+
+  String get declarationName;
+}
+
 class ParameterDeclaration {
   final String name;
 
@@ -127,3 +151,7 @@ class ParameterDeclaration {
       ..type = type.emit(TypeOptions(nullable: optional)));
   }
 }
+
+abstract class NamedType extends Type {
+  String get name;
+}

web_generator/lib/src/ast/builtin.dart

@@ -12,7 +12,7 @@ import 'base.dart';
 
 /// A built in type supported by `dart:js_interop` or by this library
 /// (with generated declarations)
-class BuiltinType extends Type {
+class BuiltinType extends NamedType {
   @override
   final String name;
 
@@ -21,15 +21,15 @@ class BuiltinType extends Type {
   /// Whether the given type is present in "dart:js_interop"
   final bool fromDartJSInterop;
 
-  // TODO(nikeokoronkwo): Types in general should have an `isNullable`
-  //  property on them to indicate nullability for Dart generated code.
-  final bool? isNullable;
+  @override
+  bool isNullable;
 
   BuiltinType(
       {required this.name,
       this.typeParams = const [],
       this.fromDartJSInterop = false,
-      this.isNullable});
+      bool? isNullable})
+      : isNullable = isNullable ?? false;
 
   @override
   ID get id => ID(type: 'type', name: name);
@@ -39,16 +39,14 @@ class BuiltinType extends Type {
 
   @override
   Reference emit([TypeOptions? options]) {
-    options ??= TypeOptions();
-
     return TypeReference((t) => t
       ..symbol = name
       ..types.addAll(typeParams
           // if there is only one type param, and it is void, ignore
           .where((p) => typeParams.length != 1 || p != $voidType)
-          .map((p) => p.emit(TypeOptions())))
+          .map((p) => p.emit(options)))
       ..url = fromDartJSInterop ? 'dart:js_interop' : null
-      ..isNullable = isNullable ?? options!.nullable);
+      ..isNullable = isNullable || (options?.nullable ?? false));
   }
 
   static final BuiltinType $voidType = BuiltinType(name: 'void');
@@ -81,7 +79,10 @@ class BuiltinType extends Type {
               name: 'JSString', fromDartJSInterop: true, isNullable: isNullable)
           : BuiltinType(name: 'String', isNullable: isNullable),
       PrimitiveType.$void || PrimitiveType.undefined => $voidType,
-      PrimitiveType.any || PrimitiveType.unknown => anyType,
+      PrimitiveType.any => (isNullable ?? false)
+          ? anyType
+          : BuiltinType(name: 'JSAny', fromDartJSInterop: true),
+      PrimitiveType.unknown => anyType,
       PrimitiveType.object => BuiltinType(
           name: 'JSObject', fromDartJSInterop: true, isNullable: isNullable),
       PrimitiveType.symbol => BuiltinType(
@@ -128,13 +129,14 @@ class BuiltinType extends Type {
   }
 }
 
-class PackageWebType extends Type {
+class PackageWebType extends NamedType {
   @override
   final String name;
 
   final List<Type> typeParams;
 
-  final bool? isNullable;
+  @override
+  bool isNullable;
 
   @override
   ID get id => ID(type: 'type', name: name);
@@ -143,29 +145,29 @@ class PackageWebType extends Type {
   String? get dartName => null;
 
   PackageWebType._(
-      {required this.name, this.typeParams = const [], this.isNullable});
+      {required this.name,
+      this.typeParams = const [],
+      this.isNullable = false});
 
   @override
   Reference emit([TypeOptions? options]) {
-    options ??= TypeOptions();
-
     // TODO: We can make this a shared function as it is called a lot
     //  between types
     return TypeReference((t) => t
       ..symbol = name
       ..types.addAll(typeParams
           // if there is only one type param, and it is void, ignore
           .where((p) => typeParams.length != 1 || p != BuiltinType.$voidType)
-          .map((p) => p.emit(TypeOptions())))
+          .map((p) => p.emit(options)))
       ..url = 'package:web/web.dart'
-      ..isNullable = isNullable ?? options!.nullable);
+      ..isNullable = isNullable || (options?.nullable ?? false));
   }
 
   static PackageWebType parse(String name,
       {bool? isNullable, List<Type> typeParams = const []}) {
     return PackageWebType._(
         name: renameMap.containsKey(name) ? renameMap[name]! : name,
-        isNullable: isNullable,
+        isNullable: isNullable ?? false,
         typeParams: typeParams);
   }
 }