Implement modular compilation

lib/src/js/js_types.dart

-// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-part of js_ast;
-
-final _any = new AnyTypeRef._();
-final _unknown = new UnknownTypeRef._();
-final _null = new NullTypeRef();
-
-/// JavaScript type reference, designed to support a subset of the type systems
-/// of the Closure Compiler and TypeScript:
-/// - https://developers.google.com/closure/compiler/docs/js-for-compiler#types
-/// - https://github.com/Microsoft/TypeScript/blob/v1.8.0-beta/doc/spec.md#3
-///
-/// Note that some subtleties like "nullability" or "optionality" are handled
-/// using unions (with a [NullTypeRef] or with an "undefined" named typeref).
-/// Also, primitives aren't modeled differently than named / qualified types,
-/// as it brings little value for now. Primitive-specific type formatting is
-/// handled by the type printers (for instance, the knowledge that
-/// `number|null` is just `number` in TypeScript, and is `number?` in Closure).
-abstract class TypeRef extends Expression {
-
-  int get precedenceLevel => PRIMARY;
-
-  TypeRef();
-
-  factory TypeRef.any() => _any;
-
-  factory TypeRef.void_() => new TypeRef.named('void');
-
-  factory TypeRef.unknown() => _unknown;
-
-  factory TypeRef.generic(TypeRef rawType, Iterable<TypeRef> typeArgs) {
-    if (typeArgs.isEmpty) {
-      throw new ArgumentError.value(typeArgs, "typeArgs", "is empty");
-    }
-    return new GenericTypeRef(rawType, typeArgs.toList());
-  }
-
-  factory TypeRef.array([TypeRef elementType]) =>
-      new ArrayTypeRef(elementType);
-
-  factory TypeRef.object([TypeRef keyType, TypeRef valueType]) {
-    // TODO(ochafik): Roll out a dedicated ObjectTypeRef?
-    var rawType = new TypeRef.named('Object');
-    return keyType == null && valueType == null
-        ? rawType
-        : new GenericTypeRef(rawType, [keyType ?? _any, valueType ?? _any]);
-  }
-
-  factory TypeRef.function(
-      [TypeRef returnType, Map<Identifier, TypeRef> paramTypes]) =>
-          new FunctionTypeRef(returnType, paramTypes);
-
-  factory TypeRef.record(Map<Identifier, TypeRef> types) =>
-      new RecordTypeRef(types);
-
-  factory TypeRef.string() => new TypeRef.named('string');
-
-  factory TypeRef.number() => new TypeRef.named('number');
-
-  factory TypeRef.undefined() => new TypeRef.named('undefined');
-
-  factory TypeRef.boolean() => new TypeRef.named('boolean');
-
-  factory TypeRef.qualified(List<Identifier> path) =>
-      new QualifiedTypeRef(path);
-
-  factory TypeRef.named(String name) =>
-      new TypeRef.qualified(<Identifier>[new Identifier(name)]);
-
-  bool get isAny => this is AnyTypeRef;
-  bool get isUnknown => this is UnknownTypeRef;
-  bool get isNull => this is NullTypeRef;
-
-  TypeRef or(TypeRef other) => new UnionTypeRef([this, other]);
-
-  TypeRef orUndefined() => or(new TypeRef.undefined());
-  TypeRef orNull() => or(_null);
-
-  TypeRef toOptional() =>
-      new OptionalTypeRef(this);
-}
-
-class AnyTypeRef extends TypeRef {
-  AnyTypeRef._() : super();
-
-  factory AnyTypeRef() => _any;
-  accept(NodeVisitor visitor) => visitor.visitAnyTypeRef(this);
-  void visitChildren(NodeVisitor visitor) {}
-  _clone() => new AnyTypeRef();
-}
-
-class NullTypeRef extends QualifiedTypeRef {
-  NullTypeRef() : super([new Identifier("null")]);
-  _clone() => new NullTypeRef();
-}
-
-class UnknownTypeRef extends TypeRef {
-  UnknownTypeRef._() : super();
-
-  factory UnknownTypeRef() => _unknown;
-  accept(NodeVisitor visitor) => visitor.visitUnknownTypeRef(this);
-  void visitChildren(NodeVisitor visitor) {}
-  _clone() => new UnknownTypeRef();
-}
-
-class QualifiedTypeRef extends TypeRef {
-  final List<Identifier> path;
-  QualifiedTypeRef(this.path);
-
-  accept(NodeVisitor visitor) => visitor.visitQualifiedTypeRef(this);
-  void visitChildren(NodeVisitor visitor) =>
-      path.forEach((p) => p.accept(visitor));
-  _clone() => new QualifiedTypeRef(path);
-}
-
-class ArrayTypeRef extends TypeRef {
-  final TypeRef elementType;
-  ArrayTypeRef(this.elementType);
-  accept(NodeVisitor visitor) => visitor.visitArrayTypeRef(this);
-  void visitChildren(NodeVisitor visitor) {
-    elementType.accept(visitor);
-  }
-  _clone() => new ArrayTypeRef(elementType);
-}
-
-class GenericTypeRef extends TypeRef {
-  final TypeRef rawType;
-  final List<TypeRef> typeArgs;
-  GenericTypeRef(this.rawType, this.typeArgs);
-
-  accept(NodeVisitor visitor) => visitor.visitGenericTypeRef(this);
-  void visitChildren(NodeVisitor visitor) {
-    rawType.accept(visitor);
-    typeArgs.forEach((p) => p.accept(visitor));
-  }
-  _clone() => new GenericTypeRef(rawType, typeArgs);
-}
-
-class UnionTypeRef extends TypeRef {
-  final List<TypeRef> types;
-  UnionTypeRef(this.types);
-
-  accept(NodeVisitor visitor) => visitor.visitUnionTypeRef(this);
-  void visitChildren(NodeVisitor visitor) {
-    types.forEach((p) => p.accept(visitor));
-  }
-  _clone() => new UnionTypeRef(types);
-
-  @override
-  TypeRef or(TypeRef other) {
-    if (types.contains(other)) return this;
-    return new UnionTypeRef([]..addAll(types)..add(other));
-  }
-}
-
-class OptionalTypeRef extends TypeRef {
-  final TypeRef type;
-  OptionalTypeRef(this.type);
-
-  accept(NodeVisitor visitor) => visitor.visitOptionalTypeRef(this);
-  void visitChildren(NodeVisitor visitor) {
-    type.accept(visitor);
-  }
-  _clone() => new OptionalTypeRef(type);
-
-  @override
-  TypeRef orUndefined() => this;
-}
-
-class RecordTypeRef extends TypeRef {
-  final Map<Identifier, TypeRef> types;
-  RecordTypeRef(this.types);
-
-  accept(NodeVisitor visitor) => visitor.visitRecordTypeRef(this);
-  void visitChildren(NodeVisitor visitor) {
-    types.values.forEach((p) => p.accept(visitor));
-  }
-  _clone() => new RecordTypeRef(types);
-}
-
-class FunctionTypeRef extends TypeRef {
-  final TypeRef returnType;
-  final Map<Identifier, TypeRef> paramTypes;
-  FunctionTypeRef(this.returnType, this.paramTypes);
-
-  accept(NodeVisitor visitor) => visitor.visitFunctionTypeRef(this);
-  void visitChildren(NodeVisitor visitor) {
-    returnType.accept(visitor);
-    paramTypes.forEach((n, t) {
-      n.accept(visitor);
-      t.accept(visitor);
-    });
-  }
-  _clone() => new FunctionTypeRef(returnType, paramTypes);
-}