Support enums in dart2js.

pkg/compiler/lib/src/resolution/enum_creator.dart

+// Copyright (c) 2014, 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.
+
+library dart2js.resolution.enum_creator;
+
+import '../dart_types.dart';
+import '../dart2jslib.dart';
+import '../elements/elements.dart';
+import '../elements/modelx.dart';
+import '../scanner/scannerlib.dart';
+import '../tree/tree.dart';
+import '../util/util.dart';
+
+// TODO(johnniwinther): Merge functionality with the `TreePrinter`.
+class AstBuilder {
+  final Token position;
+
+  AstBuilder(this.position);
+
+  int get charOffset => position.charOffset;
+
+  final Modifiers finalModifiers =
+      new Modifiers.withFlags(null, Modifiers.FLAG_FINAL);
+  final Modifiers constModifiers =
+      new Modifiers.withFlags(null, Modifiers.FLAG_CONST);
+  final Modifiers staticConstModifiers =
+      new Modifiers.withFlags(null,
+          Modifiers.FLAG_STATIC | Modifiers.FLAG_CONST);
+
+  Token keywordToken(String text) {
+    return new KeywordToken(Keyword.keywords[text], position.charOffset);
+  }
+
+  Token stringToken(String text) {
+    return new StringToken.fromString(IDENTIFIER_INFO, text, charOffset);
+  }
+
+  Token symbolToken(PrecedenceInfo info) {
+    return new SymbolToken(info, charOffset);
+  }
+
+  Identifier identifier(String text) {
+    Keyword keyword = Keyword.keywords[text];
+    Token token;
+    if (keyword != null) {
+      token = new KeywordToken(Keyword.keywords[text], charOffset);
+    } else {
+      token = stringToken(text);
+    }
+    return new Identifier(token);
+  }
+
+  Link linkedList(List elements) {
+    LinkBuilder builder = new LinkBuilder();
+    elements.forEach((e) => builder.addLast(e));
+    return builder.toLink();
+  }
+
+  NodeList argumentList(List<Node> nodes) {
+    return new NodeList(symbolToken(OPEN_PAREN_INFO),
+                        linkedList(nodes),
+                        symbolToken(CLOSE_PAREN_INFO),
+                        ',');
+  }
+
+  Return returnStatement(Expression expression) {
+    return new Return(
+        keywordToken('return'),
+        symbolToken(SEMICOLON_INFO),
+        expression);
+  }
+
+  FunctionExpression functionExpression(Modifiers modifiers,
+                                        String name,
+                                        NodeList argumentList,
+                                        Statement body,
+                                        [TypeAnnotation returnType]) {
+    return new FunctionExpression(
+        identifier(name),
+        argumentList,
+        body,
+        returnType,
+        modifiers,
+        null, // Initializer.
+        null, // get/set.
+        null  // Async modifier.
+        );
+  }
+
+  EmptyStatement emptyStatement() {
+    return new EmptyStatement(symbolToken(COMMA_INFO));
+  }
+
+  LiteralInt literalInt(int value) {
+    return new LiteralInt(stringToken('$value'), null);
+  }
+
+  LiteralString literalString(String text,
+                              {String prefix: '"',
+                                String suffix: '"'}) {
+    return new LiteralString(stringToken('$prefix$text$suffix'),
+                             new DartString.literal(text));
+  }
+
+  LiteralList listLiteral(List<Node> elements, {bool isConst: false}) {
+    return new LiteralList(
+        null,
+        new NodeList(symbolToken(OPEN_SQUARE_BRACKET_INFO),
+                     linkedList(elements),
+                     symbolToken(CLOSE_SQUARE_BRACKET_INFO),
+                     ','),
+        isConst ? keywordToken('const') : null);
+  }
+
+  Node createDefinition(Identifier name, Expression initializer) {
+    if (initializer == null) return name;
+    return new SendSet(null, name, new Operator(symbolToken(EQ_INFO)),
+                 new NodeList.singleton(initializer));
+  }
+
+  VariableDefinitions initializingFormal(String fieldName) {
+    return new VariableDefinitions.forParameter(
+        new NodeList.empty(),
+        null,
+        Modifiers.EMPTY,
+        new NodeList.singleton(
+            new Send(identifier('this'), identifier(fieldName))));
+  }
+
+  NewExpression newExpression(String typeName,
+                              NodeList arguments,
+                              {bool isConst: false}) {
+    return new NewExpression(keywordToken(isConst ? 'const' : 'new'),
+        new Send(null, identifier(typeName), arguments));
+  }
+
+}
+
+class EnumCreator {
+  final Compiler compiler;
+  final EnumClassElementX enumClass;
+
+  EnumCreator(this.compiler, this.enumClass);
+
+  void createMembers() {
+    Enum node = enumClass.node;
+    InterfaceType enumType = enumClass.thisType;
+    AstBuilder builder = new AstBuilder(enumClass.position);
+
+    InterfaceType intType = compiler.intClass.computeType(compiler);
+    InterfaceType stringType = compiler.stringClass.computeType(compiler);
+
+    EnumFieldElementX addInstanceMember(String name, InterfaceType type) {
+      Identifier identifier = builder.identifier(name);
+      VariableList variableList = new VariableList(builder.finalModifiers);
+      variableList.type = type;
+      EnumFieldElementX variable = new EnumFieldElementX(
+          identifier, enumClass, variableList, identifier);
+      enumClass.addMember(variable, compiler);
+      return variable;
+    }
+
+    EnumFieldElementX indexVariable = addInstanceMember('index', intType);
+    EnumFieldElementX nameVariable = addInstanceMember('_name', stringType);
+
+    VariableDefinitions indexDefinition = builder.initializingFormal('index');
+    VariableDefinitions nameDefinition = builder.initializingFormal('_name');
+
+    FunctionExpression constructorNode = builder.functionExpression(
+        builder.constModifiers,
+        enumClass.name,
+        builder.argumentList([indexDefinition, nameDefinition]),
+        builder.emptyStatement());
+
+    EnumConstructorElementX constructor = new EnumConstructorElementX(
+        enumClass,
+        builder.constModifiers,
+        constructorNode);
+
+    EnumFormalElementX indexFormal = new EnumFormalElementX(
+        constructor,
+        indexDefinition,
+        builder.identifier('index'),
+        indexVariable);
+
+    EnumFormalElementX nameFormal = new EnumFormalElementX(
+        constructor,
+        nameDefinition,
+        builder.identifier('_name'),
+        nameVariable);
+
+    FunctionSignatureX constructorSignature = new FunctionSignatureX(
+        requiredParameters: builder.linkedList([indexFormal, nameFormal]),
+        requiredParameterCount: 2,
+        type: new FunctionType(constructor, const VoidType(),
+            <DartType>[intType, stringType]));
+    constructor.functionSignatureCache = constructorSignature;
+    enumClass.addMember(constructor, compiler);
+
+    VariableList variableList = new VariableList(builder.staticConstModifiers);
+    variableList.type = enumType;
+    int index = 0;
+    List<Node> valueReferences = <Node>[];
+    for (Link<Node> link = node.names.nodes;
+         !link.isEmpty;
+         link = link.tail) {
+      Identifier name = link.head;
+      AstBuilder valueBuilder = new AstBuilder(name.token);
+      valueReferences.add(new Send(null, name));
+
+      Expression initializer = valueBuilder.newExpression(
+          enumClass.name,
+          valueBuilder.argumentList([
+            valueBuilder.literalInt(index),
+            valueBuilder.literalString('${name.source}')
+          ]),
+          isConst: true);
+      SendSet definition = valueBuilder.createDefinition(name, initializer);
+
+      EnumFieldElementX field = new EnumFieldElementX(
+          name, enumClass, variableList, definition, initializer);
+      enumClass.addMember(field, compiler);
+      index++;
+    }
+
+    VariableList valuesVariableList =
+        new VariableList(builder.staticConstModifiers);
+    InterfaceType listType = compiler.listClass.computeType(compiler);
+    valuesVariableList.type = listType.createInstantiation([enumType]);
+
+    Identifier valuesIdentifier = builder.identifier('values');
+    // TODO(johnniwinther): Add type argument.
+    Expression initializer = builder.listLiteral(
+        valueReferences, isConst: true);
+
+    Node definition = builder.createDefinition(valuesIdentifier, initializer);
+
+    EnumFieldElementX valuesVariable = new EnumFieldElementX(
+        valuesIdentifier, enumClass, valuesVariableList,
+        definition, initializer);
+
+    enumClass.addMember(valuesVariable, compiler);
+
+    // TODO(johnniwinther): Support return type. Note `String` might be prefixed
+    // or not imported within the current library.
+    FunctionExpression toStringNode = builder.functionExpression(
+        Modifiers.EMPTY,
+        'toString',
+        builder.argumentList([]),
+        builder.returnStatement(
+            new StringInterpolation(
+                builder.literalString('${enumClass.name}.', suffix: ''),
+                new NodeList.singleton(new StringInterpolationPart(
+                    new Send(null, builder.identifier('_name')),
+                    builder.literalString('', prefix: '')))
+            ))
+        );
+
+    EnumMethodElementX toString = new EnumMethodElementX('toString',
+        enumClass, Modifiers.EMPTY, toStringNode);
+    FunctionSignatureX toStringSignature = new FunctionSignatureX(
+        type: new FunctionType(toString, stringType));
+    toString.functionSignatureCache = toStringSignature;
+    enumClass.addMember(toString, compiler);
+  }
+}