Move frog/leg to lib/compiler/implementation.

frog/leg/tree/nodes.dart

Index: frog/leg/tree/nodes.dart
===================================================================
--- frog/leg/tree/nodes.dart	(revision 5925)
+++ frog/leg/tree/nodes.dart	(working copy)
@@ -1,1644 +0,0 @@
-// Copyright (c) 2012, 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.
-
-interface Visitor<R> {
-  R visitBlock(Block node);
-  R visitBreakStatement(BreakStatement node);
-  R visitCatchBlock(CatchBlock node);
-  R visitClassNode(ClassNode node);
-  R visitConditional(Conditional node);
-  R visitContinueStatement(ContinueStatement node);
-  R visitDoWhile(DoWhile node);
-  R visitEmptyStatement(EmptyStatement node);
-  R visitExpressionStatement(ExpressionStatement node);
-  R visitFor(For node);
-  R visitForInStatement(ForInStatement node);
-  R visitFunctionDeclaration(FunctionDeclaration node);
-  R visitFunctionExpression(FunctionExpression node);
-  R visitIdentifier(Identifier node);
-  R visitIf(If node);
-  R visitLabeledStatement(LabeledStatement node);
-  R visitLiteralBool(LiteralBool node);
-  R visitLiteralDouble(LiteralDouble node);
-  R visitLiteralInt(LiteralInt node);
-  R visitLiteralList(LiteralList node);
-  R visitLiteralMap(LiteralMap node);
-  R visitLiteralMapEntry(LiteralMapEntry node);
-  R visitLiteralNull(LiteralNull node);
-  R visitLiteralString(LiteralString node);
-  R visitStringJuxtaposition(StringJuxtaposition node);
-  R visitModifiers(Modifiers node);
-  R visitNamedArgument(NamedArgument node);
-  R visitNewExpression(NewExpression node);
-  R visitNodeList(NodeList node);
-  R visitOperator(Operator node);
-  R visitParenthesizedExpression(ParenthesizedExpression node);
-  R visitReturn(Return node);
-  R visitScriptTag(ScriptTag node);
-  R visitSend(Send node);
-  R visitSendSet(SendSet node);
-  R visitStringInterpolation(StringInterpolation node);
-  R visitStringInterpolationPart(StringInterpolationPart node);
-  R visitSwitchCase(SwitchCase node);
-  R visitSwitchStatement(SwitchStatement node);
-  R visitThrow(Throw node);
-  R visitTryStatement(TryStatement node);
-  R visitTypeAnnotation(TypeAnnotation node);
-  R visitTypedef(Typedef node);
-  R visitTypeVariable(TypeVariable node);
-  R visitVariableDefinitions(VariableDefinitions node);
-  R visitWhile(While node);
-}
-
-Token firstBeginToken(Node first, Node second) {
-  if (first !== null) return first.getBeginToken();
-  if (second !== null) return second.getBeginToken();
-  return null;
-}
-
-class NodeAssertionFailure implements Exception {
-  final Node node;
-  final String message;
-  NodeAssertionFailure(this.node, this.message);
-}
-
-/**
- * A node in a syntax tree.
- *
- * The abstract part of "abstract syntax tree" is invalidated when
- * supporting tools such as code formatting. These tools need concrete
- * syntax such as parentheses and no constant folding.
- *
- * We support these tools by storing additional references back to the
- * token stream. These references are stored in fields ending with
- * "Token".
- */
-class Node implements Hashable {
-  final int _hashCode;
-  static int _HASH_COUNTER = 0;
-
-  Node() : _hashCode = ++_HASH_COUNTER;
-
-  hashCode() => _hashCode;
-
-  abstract accept(Visitor visitor);
-
-  abstract visitChildren(Visitor visitor);
-
-  toString() => unparse(false);
-
-  toDebugString() => unparse(true);
-
-  String getObjectDescription() => super.toString();
-
-  String unparse(bool printDebugInfo) {
-    Unparser unparser = new Unparser(printDebugInfo);
-    try {
-      return unparser.unparse(this);
-    } catch (var e, var trace) {
-      print(trace);
-      return '<<unparse error: ${getObjectDescription()}: ${unparser.sb}>>';
-    }
-  }
-
-  abstract Token getBeginToken();
-
-  abstract Token getEndToken();
-
-  Block asBlock() => null;
-  BreakStatement asBreakStatement() => null;
-  CatchBlock asCatchBlock() => null;
-  ClassNode asClassNode() => null;
-  Conditional asConditional() => null;
-  ContinueStatement asContinueStatement() => null;
-  DoWhile asDoWhile() => null;
-  EmptyStatement asEmptyStatement() => null;
-  Expression asExpression() => null;
-  ExpressionStatement asExpressionStatement() => null;
-  For asFor() => null;
-  ForInStatement asForInStatement() => null;
-  FunctionDeclaration asFunctionDeclaration() => null;
-  FunctionExpression asFunctionExpression() => null;
-  Identifier asIdentifier() => null;
-  If asIf() => null;
-  LabeledStatement asLabeledStatement() => null;
-  LiteralBool asLiteralBool() => null;
-  LiteralDouble asLiteralDouble() => null;
-  LiteralInt asLiteralInt() => null;
-  LiteralList asLiteralList() => null;
-  LiteralMap asLiteralMap() => null;
-  LiteralMapEntry asLiteralMapEntry() => null;
-  LiteralNull asLiteralNull() => null;
-  LiteralString asLiteralString() => null;
-  Modifiers asModifiers() => null;
-  NamedArgument asNamedArgument() => null;
-  NodeList asNodeList() => null;
-  Operator asOperator() => null;
-  ParenthesizedExpression asParenthesizedExpression() => null;
-  Return asReturn() => null;
-  ScriptTag asScriptTag() => null;
-  Send asSend() => null;
-  SendSet asSendSet() => null;
-  Statement asStatement() => null;
-  StringInterpolation asStringInterpolation() => null;
-  StringInterpolationPart asStringInterpolationPart() => null;
-  StringJuxtaposition asStringJuxtaposition() => null;
-  SwitchCase asSwitchCase() => null;
-  SwitchStatement asSwitchStatement() => null;
-  Throw asThrow() => null;
-  TryStatement asTryStatement() => null;
-  TypeAnnotation asTypeAnnotation() => null;
-  Typedef asTypedef() => null;
-  TypeVariable asTypeVariable() => null;
-  VariableDefinitions asVariableDefinitions() => null;
-  While asWhile() => null;
-
-  bool isValidBreakTarget() => false;
-  bool isValidContinueTarget() => false;
-}
-
-class ClassNode extends Node {
-  final Identifier name;
-  final TypeAnnotation superclass;
-  final NodeList interfaces;
-  final NodeList typeParameters;
-
-  // TODO(ahe, karlklose): the default keyword is not recorded.
-  final TypeAnnotation defaultClause;
-
-  final Token beginToken;
-  final Token extendsKeyword;
-  final Token endToken;
-
-  ClassNode(this.name, this.typeParameters, this.superclass, this.interfaces,
-            this.defaultClause, this.beginToken, this.extendsKeyword,
-            this.endToken);
-
-  ClassNode asClassNode() => this;
-
-  accept(Visitor visitor) => visitor.visitClassNode(this);
-
-  visitChildren(Visitor visitor) {
-    if (name !== null) name.accept(visitor);
-    if (superclass !== null) superclass.accept(visitor);
-    if (interfaces !== null) interfaces.accept(visitor);
-  }
-
-  bool get isInterface() => beginToken.stringValue === 'interface';
-
-  bool get isClass() => !isInterface;
-
-  Token getBeginToken() => beginToken;
-
-  Token getEndToken() => endToken;
-}
-
-class Expression extends Node {
-  Expression();
-
-  Expression asExpression() => this;
-
-  // TODO(ahe): make class abstract instead of adding an abstract method.
-  abstract accept(Visitor visitor);
-}
-
-class Statement extends Node {
-  Statement();
-
-  Statement asStatement() => this;
-
-  // TODO(ahe): make class abstract instead of adding an abstract method.
-  abstract accept(Visitor visitor);
-
-  bool isValidBreakTarget() => true;
-}
-
-/**
- * A message send aka method invocation. In Dart, most operations can
- * (and should) be considered as message sends. Getters and setters
- * are just methods with a special syntax. Consequently, we model
- * property access, assignment, operators, and method calls with this
- * one node.
- */
-class Send extends Expression {
-  final Node receiver;
-  final Node selector;
-  final NodeList argumentsNode;
-  Link<Node> get arguments() => argumentsNode.nodes;
-
-  Send([this.receiver, this.selector, this.argumentsNode]);
-  Send.postfix(this.receiver, this.selector, [Node argument = null])
-      : argumentsNode = (argument === null)
-        ? new Postfix()
-        : new Postfix.singleton(argument);
-  Send.prefix(this.receiver, this.selector, [Node argument = null])
-      : argumentsNode = (argument === null)
-        ? new Prefix()
-        : new Prefix.singleton(argument);
-
-  Send asSend() => this;
-
-  accept(Visitor visitor) => visitor.visitSend(this);
-
-  visitChildren(Visitor visitor) {
-    if (receiver !== null) receiver.accept(visitor);
-    if (selector !== null) selector.accept(visitor);
-    if (argumentsNode !== null) argumentsNode.accept(visitor);
-  }
-
-  int argumentCount() => argumentsNode.length();
-
-  bool get isSuperCall() {
-    return receiver !== null &&
-           receiver.asIdentifier() !== null &&
-           receiver.asIdentifier().isSuper();
-  }
-  bool get isOperator() => selector is Operator;
-  bool get isPropertyAccess() => argumentsNode === null;
-  bool get isFunctionObjectInvocation() => selector === null;
-  bool get isPrefix() => argumentsNode is Prefix;
-  bool get isPostfix() => argumentsNode is Postfix;
-  bool get isIndex() =>
-      isOperator && selector.asOperator().source.stringValue === '[]';
-
-  Token getBeginToken() {
-    if (isPrefix && !isIndex) return selector.getBeginToken();
-    return firstBeginToken(receiver, selector);
-  }
-
-  Token getEndToken() {
-    if (isPrefix) {
-      if (receiver !== null) return receiver.getEndToken();
-      if (selector !== null) return selector.getEndToken();
-      return null;
-    }
-    if (!isPostfix && argumentsNode !== null) {
-      return argumentsNode.getEndToken();
-    }
-    if (selector !== null) return selector.getEndToken();
-    return receiver.getBeginToken();
-  }
-
-  Send copyWithReceiver(Node newReceiver) {
-    assert(receiver === null);
-    return new Send(newReceiver, selector, argumentsNode);
-  }
-}
-
-class Postfix extends NodeList {
-  Postfix() : super(nodes: const EmptyLink<Node>());
-  Postfix.singleton(Node argument) : super.singleton(argument);
-}
-
-class Prefix extends NodeList {
-  Prefix() : super(nodes: const EmptyLink<Node>());
-  Prefix.singleton(Node argument) : super.singleton(argument);
-}
-
-class SendSet extends Send {
-  final Operator assignmentOperator;
-  SendSet(receiver, selector, this.assignmentOperator, argumentsNode)
-    : super(receiver, selector, argumentsNode);
-  SendSet.postfix(receiver,
-                  selector,
-                  this.assignmentOperator,
-                  [Node argument = null])
-      : super.postfix(receiver, selector, argument);
-  SendSet.prefix(receiver,
-                 selector,
-                 this.assignmentOperator,
-                 [Node argument = null])
-      : super.prefix(receiver, selector, argument);
-
-  SendSet asSendSet() => this;
-
-  accept(Visitor visitor) => visitor.visitSendSet(this);
-
-  visitChildren(Visitor visitor) {
-    super.visitChildren(visitor);
-    if (assignmentOperator !== null) assignmentOperator.accept(visitor);
-  }
-
-  Send copyWithReceiver(Node newReceiver) {
-    assert(receiver === null);
-    return new SendSet(newReceiver, selector, assignmentOperator,
-                       argumentsNode);
-  }
-}
-
-class NewExpression extends Expression {
-  /** The token NEW or CONST */
-  final Token newToken;
-
-  // Note: we expect that send.receiver is null.
-  final Send send;
-
-  NewExpression([this.newToken, this.send]);
-
-  accept(Visitor visitor) => visitor.visitNewExpression(this);
-
-  visitChildren(Visitor visitor) {
-    if (send !== null) send.accept(visitor);
-  }
-
-  bool isConst() => newToken.stringValue === 'const';
-
-  Token getBeginToken() => newToken;
-
-  Token getEndToken() => send.getEndToken();
-}
-
-class NodeList extends Node implements Iterable<Node> {
-  final Link<Node> nodes;
-  final Token beginToken;
-  final Token endToken;
-  final SourceString delimiter;
-  bool isEmpty() => nodes.isEmpty();
-
-  NodeList([this.beginToken, this.nodes, this.endToken, this.delimiter]);
-
-  Iterator<Node> iterator() => nodes.iterator();
-
-  NodeList.singleton(Node node) : this(null, new Link<Node>(node));
-  NodeList.empty() : this(null, const EmptyLink<Node>());
-
-  NodeList asNodeList() => this;
-
-  int length() {
-    int result = 0;
-    for (Link<Node> cursor = nodes; !cursor.isEmpty(); cursor = cursor.tail) {
-      result++;
-    }
-    return result;
-  }
-
-  accept(Visitor visitor) => visitor.visitNodeList(this);
-
-  visitChildren(Visitor visitor) {
-    if (nodes === null) return;
-    for (Link<Node> link = nodes; !link.isEmpty(); link = link.tail) {
-      if (link.head !== null) link.head.accept(visitor);
-    }
-  }
-
-  Token getBeginToken() {
-    if (beginToken !== null) return beginToken;
-     if (nodes !== null) {
-       for (Link<Node> link = nodes; !link.isEmpty(); link = link.tail) {
-         if (link.head.getBeginToken() !== null) {
-           return link.head.getBeginToken();
-         }
-         if (link.head.getEndToken() !== null) {
-           return link.head.getEndToken();
-         }
-       }
-     }
-    return endToken;
-  }
-
-  Token getEndToken() {
-    if (endToken !== null) return endToken;
-    if (nodes !== null) {
-      Link<Node> link = nodes;
-      if (link.isEmpty()) return beginToken;
-      while (!link.tail.isEmpty()) link = link.tail;
-      if (link.head.getEndToken() !== null) return link.head.getEndToken();
-      if (link.head.getBeginToken() !== null) return link.head.getBeginToken();
-    }
-    return beginToken;
-  }
-}
-
-class Block extends Statement {
-  final NodeList statements;
-
-  Block(this.statements);
-
-  Block asBlock() => this;
-
-  accept(Visitor visitor) => visitor.visitBlock(this);
-
-  visitChildren(Visitor visitor) {
-    if (statements !== null) statements.accept(visitor);
-  }
-
-  Token getBeginToken() => statements.getBeginToken();
-
-  Token getEndToken() => statements.getEndToken();
-}
-
-class If extends Statement {
-  final ParenthesizedExpression condition;
-  final Statement thenPart;
-  final Statement elsePart;
-
-  final Token ifToken;
-  final Token elseToken;
-
-  If(this.condition, this.thenPart, this.elsePart,
-     this.ifToken, this.elseToken);
-
-  If asIf() => this;
-
-  bool get hasElsePart() => elsePart !== null;
-
-  void validate() {
-    // TODO(ahe): Check that condition has size one.
-  }
-
-  accept(Visitor visitor) => visitor.visitIf(this);
-
-  visitChildren(Visitor visitor) {
-    if (condition !== null) condition.accept(visitor);
-    if (thenPart !== null) thenPart.accept(visitor);
-    if (elsePart !== null) elsePart.accept(visitor);
-  }
-
-  Token getBeginToken() => ifToken;
-
-  Token getEndToken() {
-    if (elsePart === null) return thenPart.getEndToken();
-    return elsePart.getEndToken();
-  }
-}
-
-class Conditional extends Expression {
-  final Expression condition;
-  final Expression thenExpression;
-  final Expression elseExpression;
-
-  final Token questionToken;
-  final Token colonToken;
-
-  Conditional(this.condition, this.thenExpression,
-              this.elseExpression, this.questionToken, this.colonToken);
-
-  Conditional asConditional() => this;
-
-  accept(Visitor visitor) => visitor.visitConditional(this);
-
-  visitChildren(Visitor visitor) {
-    condition.accept(visitor);
-    thenExpression.accept(visitor);
-    elseExpression.accept(visitor);
-  }
-
-  Token getBeginToken() => condition.getBeginToken();
-
-  Token getEndToken() => elseExpression.getEndToken();
-}
-
-class For extends Loop {
-  /** Either a variable declaration or an expression. */
-  final Node initializer;
-  /** Either an expression statement or an empty statement. */
-  final Statement conditionStatement;
-  final NodeList update;
-
-  final Token forToken;
-
-  For(this.initializer, this.conditionStatement, this.update, body,
-      this.forToken) : super(body);
-
-  For asFor() => this;
-
-  Expression get condition() {
-    if (conditionStatement is ExpressionStatement) {
-      return conditionStatement.asExpressionStatement().expression;
-    } else {
-      return null;
-    }
-  }
-
-  accept(Visitor visitor) => visitor.visitFor(this);
-
-  visitChildren(Visitor visitor) {
-    if (initializer !== null) initializer.accept(visitor);
-    if (conditionStatement !== null) conditionStatement.accept(visitor);
-    if (update !== null) update.accept(visitor);
-    if (body !== null) body.accept(visitor);
-  }
-
-  Token getBeginToken() => forToken;
-
-  Token getEndToken() {
-    return body.getEndToken();
-  }
-}
-
-class FunctionDeclaration extends Statement {
-  final FunctionExpression function;
-
-  FunctionDeclaration(this.function);
-
-  FunctionDeclaration asFunctionDeclaration() => this;
-
-  accept(Visitor visitor) => visitor.visitFunctionDeclaration(this);
-
-  visitChildren(Visitor visitor) => function.accept(visitor);
-
-  Token getBeginToken() => function.getBeginToken();
-  Token getEndToken() => function.getEndToken();
-}
-
-class FunctionExpression extends Expression {
-  final Node name;
-
-  /**
-   * List of VariableDefinitions or NodeList.
-   *
-   * A NodeList can only occur at the end and holds named parameters.
-   */
-  final NodeList parameters;
-
-  final Statement body;
-  final TypeAnnotation returnType;
-  final Modifiers modifiers;
-  final NodeList initializers;
-
-  final Token getOrSet;
-
-  FunctionExpression(this.name, this.parameters, this.body, this.returnType,
-                     this.modifiers, this.initializers, this.getOrSet);
-
-  FunctionExpression asFunctionExpression() => this;
-
-  accept(Visitor visitor) => visitor.visitFunctionExpression(this);
-
-  visitChildren(Visitor visitor) {
-    if (modifiers !== null) modifiers.accept(visitor);
-    if (returnType !== null) returnType.accept(visitor);
-    if (name !== null) name.accept(visitor);
-    if (parameters !== null) parameters.accept(visitor);
-    if (initializers !== null) initializers.accept(visitor);
-    if (body !== null) body.accept(visitor);
-  }
-
-  bool hasBody() {
-    // TODO(karlklose,ahe): refactor AST nodes (issue 1713).
-    if (body.asReturn() !== null) return true;
-    NodeList statements = body.asBlock().statements;
-    return (!statements.nodes.isEmpty() ||
-            statements.getBeginToken().kind !== $SEMICOLON);
-  }
-
-  Token getBeginToken() {
-    Token token = firstBeginToken(modifiers, returnType);
-    if (token !== null) return token;
-    if (getOrSet !== null) return getOrSet;
-    return firstBeginToken(name, parameters);
-  }
-
-  Token getEndToken() {
-    Token token = (body === null) ? null : body.getEndToken();
-    token = (token === null) ? parameters.getEndToken() : token;
-    return (token === null) ? name.getEndToken() : token;
-  }
-}
-
-typedef void DecodeErrorHandler(Token token, var error);
-
-class Literal<T> extends Expression {
-  final Token token;
-  final DecodeErrorHandler handler;
-
-  Literal(Token this.token, DecodeErrorHandler this.handler);
-
-  abstract T get value();
-
-  visitChildren(Visitor visitor) {}
-
-  Token getBeginToken() => token;
-
-  Token getEndToken() => token;
-}
-
-class LiteralInt extends Literal<int> {
-  LiteralInt(Token token, DecodeErrorHandler handler) : super(token, handler);
-
-  LiteralInt asLiteralInt() => this;
-
-  int get value() {
-    try {
-      Token token = this.token;
-      if (token.kind === PLUS_TOKEN) token = token.next;
-      return Math.parseInt(token.value.slowToString());
-    } catch (BadNumberFormatException ex) {
-      (this.handler)(token, ex);
-    }
-  }
-
-  accept(Visitor visitor) => visitor.visitLiteralInt(this);
-}
-
-class LiteralDouble extends Literal<double> {
-  LiteralDouble(Token token, DecodeErrorHandler handler)
-    : super(token, handler);
-
-  LiteralDouble asLiteralDouble() => this;
-
-  double get value() {
-    try {
-      Token token = this.token;
-      if (token.kind === PLUS_TOKEN) token = token.next;
-      return Math.parseDouble(token.value.slowToString());
-    } catch (BadNumberFormatException ex) {
-      (this.handler)(token, ex);
-    }
-  }
-
-  accept(Visitor visitor) => visitor.visitLiteralDouble(this);
-}
-
-class LiteralBool extends Literal<bool> {
-  LiteralBool(Token token, DecodeErrorHandler handler) : super(token, handler);
-
-  LiteralBool asLiteralBool() => this;
-
-  bool get value() {
-    switch (token.value) {
-      case Keyword.TRUE: return true;
-      case Keyword.FALSE: return false;
-      default:
-        (this.handler)(token, "not a bool ${token.value}");
-    }
-  }
-
-  accept(Visitor visitor) => visitor.visitLiteralBool(this);
-}
-
-
-class StringQuoting {
-  static final StringQuoting SINGLELINE_DQ =
-      const StringQuoting($DQ, raw: false, leftQuoteLength: 1);
-  static final StringQuoting RAW_SINGLELINE_DQ =
-      const StringQuoting($DQ, raw: true, leftQuoteLength: 1);
-  static final StringQuoting MULTILINE_DQ =
-      const StringQuoting($DQ, raw: false, leftQuoteLength: 3);
-  static final StringQuoting RAW_MULTILINE_DQ =
-      const StringQuoting($DQ, raw: true, leftQuoteLength: 3);
-  static final StringQuoting MULTILINE_NL_DQ =
-      const StringQuoting($DQ, raw: false, leftQuoteLength: 4);
-  static final StringQuoting RAW_MULTILINE_NL_DQ =
-      const StringQuoting($DQ, raw: true, leftQuoteLength: 4);
-  static final StringQuoting MULTILINE_NL2_DQ =
-      const StringQuoting($DQ, raw: false, leftQuoteLength: 5);
-  static final StringQuoting RAW_MULTILINE_NL2_DQ =
-      const StringQuoting($DQ, raw: true, leftQuoteLength: 5);
-  static final StringQuoting SINGLELINE_SQ =
-      const StringQuoting($SQ, raw: false, leftQuoteLength: 1);
-  static final StringQuoting RAW_SINGLELINE_SQ =
-      const StringQuoting($SQ, raw: true, leftQuoteLength: 1);
-  static final StringQuoting MULTILINE_SQ =
-      const StringQuoting($SQ, raw: false, leftQuoteLength: 3);
-  static final StringQuoting RAW_MULTILINE_SQ =
-      const StringQuoting($SQ, raw: true, leftQuoteLength: 3);
-  static final StringQuoting MULTILINE_NL_SQ =
-      const StringQuoting($SQ, raw: false, leftQuoteLength: 4);
-  static final StringQuoting RAW_MULTILINE_NL_SQ =
-      const StringQuoting($SQ, raw: true, leftQuoteLength: 4);
-  static final StringQuoting MULTILINE_NL2_SQ =
-      const StringQuoting($SQ, raw: false, leftQuoteLength: 5);
-  static final StringQuoting RAW_MULTILINE_NL2_SQ =
-      const StringQuoting($SQ, raw: true, leftQuoteLength: 5);
-
-
-  static final List<StringQuoting> mapping = const <StringQuoting>[
-    SINGLELINE_DQ,
-    RAW_SINGLELINE_DQ,
-    MULTILINE_DQ,
-    RAW_MULTILINE_DQ,
-    MULTILINE_NL_DQ,
-    RAW_MULTILINE_NL_DQ,
-    MULTILINE_NL2_DQ,
-    RAW_MULTILINE_NL2_DQ,
-    SINGLELINE_SQ,
-    RAW_SINGLELINE_SQ,
-    MULTILINE_SQ,
-    RAW_MULTILINE_SQ,
-    MULTILINE_NL_SQ,
-    RAW_MULTILINE_NL_SQ,
-    MULTILINE_NL2_SQ,
-    RAW_MULTILINE_NL2_SQ
-  ];
-  final bool raw;
-  final int leftQuoteCharCount;
-  final int quote;
-  const StringQuoting(this.quote, [bool raw, int leftQuoteLength])
-      : this.raw = raw, this.leftQuoteCharCount = leftQuoteLength;
-  String get quoteChar() => quote === $DQ ? '"' : "'";
-
-  int get leftQuoteLength() => (raw ? 1 : 0) + leftQuoteCharCount;
-  int get rightQuoteLength() => (leftQuoteCharCount > 2) ? 3 : 1;
-  static StringQuoting getQuoting(int quote, bool raw, int quoteLength) {
-    int index = quoteLength - 1;
-    if (quoteLength > 2) index -= 1;
-    return mapping[(raw ? 1 : 0) + index * 2 + (quote === $SQ ? 8 : 0)];
-  }
-}
-
-/**
-  * Superclass for classes representing string literals.
-  */
-class StringNode extends Expression {
-  abstract DartString get dartString();
-  abstract bool get isInterpolation();
-}
-
-class LiteralString extends StringNode {
-  final Token token;
-  /** Non-null on validated string literals. */
-  final DartString dartString;
-
-  LiteralString(this.token, this.dartString);
-
-  LiteralString asLiteralString() => this;
-
-  void visitChildren(Visitor visitor) {}
-
-  bool get isInterpolation() => false;
-  bool isValidated() => dartString !== null;
-
-  Token getBeginToken() => token;
-  Token getEndToken() => token;
-
-  accept(Visitor visitor) => visitor.visitLiteralString(this);
-}
-
-class LiteralNull extends Literal<SourceString> {
-  LiteralNull(Token token) : super(token, null);
-
-  LiteralNull asLiteralNull() => this;
-
-  SourceString get value() => null;
-
-  accept(Visitor visitor) => visitor.visitLiteralNull(this);
-}
-
-class LiteralList extends Expression {
-  final TypeAnnotation type;
-  final NodeList elements;
-
-  final Token constKeyword;
-
-  LiteralList(this.type, this.elements, this.constKeyword);
-
-  bool isConst() => constKeyword !== null;
-
-  LiteralList asLiteralList() => this;
-  accept(Visitor visitor) => visitor.visitLiteralList(this);
-
-  visitChildren(Visitor visitor) {
-    if (type !== null) type.accept(visitor);
-    elements.accept(visitor);
-  }
-
-  Token getBeginToken() {
-    if (constKeyword !== null) return constKeyword;
-    return firstBeginToken(type, elements);
-  }
-
-  Token getEndToken() => elements.getEndToken();
-}
-
-class Identifier extends Expression {
-  final Token token;
-
-  SourceString get source() => token.value;
-
-  Identifier(Token this.token);
-
-  bool isThis() => source.stringValue === 'this';
-
-  bool isSuper() => source.stringValue === 'super';
-
-  Identifier asIdentifier() => this;
-
-  accept(Visitor visitor) => visitor.visitIdentifier(this);
-
-  visitChildren(Visitor visitor) {}
-
-  Token getBeginToken() => token;
-
-  Token getEndToken() => token;
-}
-
-class Operator extends Identifier {
-  Operator(Token token) : super(token);
-
-  Operator asOperator() => this;
-
-  accept(Visitor visitor) => visitor.visitOperator(this);
-}
-
-class Return extends Statement {
-  final Expression expression;
-  final Token beginToken;
-  final Token endToken;
-
-  Return(this.beginToken, this.endToken, this.expression);
-
-  Return asReturn() => this;
-
-  bool get hasExpression() => expression !== null;
-
-  accept(Visitor visitor) => visitor.visitReturn(this);
-
-  visitChildren(Visitor visitor) {
-    if (expression !== null) expression.accept(visitor);
-  }
-
-  Token getBeginToken() => beginToken;
-
-  Token getEndToken() {
-    if (endToken === null) return expression.getEndToken();
-    return endToken;
-  }
-}
-
-class ExpressionStatement extends Statement {
-  final Expression expression;
-  final Token endToken;
-
-  ExpressionStatement(this.expression, this.endToken);
-
-  ExpressionStatement asExpressionStatement() => this;
-
-  accept(Visitor visitor) => visitor.visitExpressionStatement(this);
-
-  visitChildren(Visitor visitor) {
-    if (expression !== null) expression.accept(visitor);
-  }
-
-  Token getBeginToken() => expression.getBeginToken();
-
-  Token getEndToken() => endToken;
-}
-
-class Throw extends Statement {
-  final Expression expression;
-
-  final Token throwToken;
-  final Token endToken;
-
-  Throw(this.expression, this.throwToken, this.endToken);
-
-  Throw asThrow() => this;
-
-  accept(Visitor visitor) => visitor.visitThrow(this);
-
-  visitChildren(Visitor visitor) {
-    if (expression !== null) expression.accept(visitor);
-  }
-
-  Token getBeginToken() => throwToken;
-
-  Token getEndToken() => endToken;
-}
-
-class TypeAnnotation extends Node {
-  final Expression typeName;
-  final NodeList typeArguments;
-
-  TypeAnnotation(Expression this.typeName, NodeList this.typeArguments);
-
-  TypeAnnotation asTypeAnnotation() => this;
-
-  accept(Visitor visitor) => visitor.visitTypeAnnotation(this);
-
-  visitChildren(Visitor visitor) {
-    typeName.accept(visitor);
-    if (typeArguments !== null) typeArguments.accept(visitor);
-  }
-
-  Token getBeginToken() => typeName.getBeginToken();
-
-  Token getEndToken() => typeName.getEndToken();
-}
-
-class TypeVariable extends Node {
-  final Identifier name;
-  final TypeAnnotation bound;
-  TypeVariable(Identifier this.name, TypeAnnotation this.bound);
-
-  accept(Visitor visitor) => visitor.visitTypeVariable(this);
-
-  visitChildren(Visitor visitor) {
-    name.accept(visitor);
-    if (bound !== null) {
-      bound.accept(visitor);
-    }
-  }
-
-  TypeVariable asTypeVariable() => this;
-
-  Token getBeginToken() => name.getBeginToken();
-
-  Token getEndToken() {
-    return (bound !== null) ? bound.getEndToken() : name.getEndToken();
-  }
-}
-
-class VariableDefinitions extends Statement {
-  final Token endToken;
-  final TypeAnnotation type;
-  final Modifiers modifiers;
-  final NodeList definitions;
-  VariableDefinitions(this.type, this.modifiers, this.definitions,
-                      this.endToken);
-
-  VariableDefinitions asVariableDefinitions() => this;
-
-  accept(Visitor visitor) => visitor.visitVariableDefinitions(this);
-
-  visitChildren(Visitor visitor) {
-    if (type !== null) type.accept(visitor);
-    if (definitions !== null) definitions.accept(visitor);
-  }
-
-  Token getBeginToken() {
-    return firstBeginToken(type, definitions);
-  }
-
-  Token getEndToken() => endToken;
-}
-
-class Loop extends Statement {
-  abstract Expression get condition();
-  final Statement body;
-
-  Loop(this.body);
-
-  bool isValidContinueTarget() => true;
-}
-
-class DoWhile extends Loop {
-  final Token doKeyword;
-  final Token whileKeyword;
-  final Token endToken;
-
-  final Expression condition;
-
-  DoWhile(Statement body, Expression this.condition,
-          Token this.doKeyword, Token this.whileKeyword, Token this.endToken)
-    : super(body);
-
-  DoWhile asDoWhile() => this;
-
-  accept(Visitor visitor) => visitor.visitDoWhile(this);
-
-  visitChildren(Visitor visitor) {
-    if (condition !== null) condition.accept(visitor);
-    if (body !== null) body.accept(visitor);
-  }
-
-  Token getBeginToken() => doKeyword;
-
-  Token getEndToken() => endToken;
-}
-
-class While extends Loop {
-  final Token whileKeyword;
-  final Expression condition;
-
-  While(Expression this.condition, Statement body,
-        Token this.whileKeyword) : super(body);
-
-  While asWhile() => this;
-
-  accept(Visitor visitor) => visitor.visitWhile(this);
-
-  visitChildren(Visitor visitor) {
-    if (condition !== null) condition.accept(visitor);
-    if (body !== null) body.accept(visitor);
-  }
-
-  Token getBeginToken() => whileKeyword;
-
-  Token getEndToken() => body.getEndToken();
-}
-
-class ParenthesizedExpression extends Expression {
-  final Expression expression;
-  final BeginGroupToken beginToken;
-
-  ParenthesizedExpression(Expression this.expression,
-                          BeginGroupToken this.beginToken);
-
-  ParenthesizedExpression asParenthesizedExpression() => this;
-
-  accept(Visitor visitor) => visitor.visitParenthesizedExpression(this);
-
-  visitChildren(Visitor visitor) {
-    if (expression !== null) expression.accept(visitor);
-  }
-
-  Token getBeginToken() => beginToken;
-
-  Token getEndToken() => beginToken.endGroup;
-}
-
-/** Representation of modifiers such as static, abstract, final, etc. */
-class Modifiers extends Node {
-  /* TODO(ahe): The following should be validated relating to modifiers:
-   * 1. The nodes must come in a certain order.
-   * 2. The keywords "var" and "final" may not be used at the same time.
-   * 3. The type of an element must be null if isVar() is true.
-   */
-
-  final NodeList nodes;
-  /** Bit pattern to easy check what modifiers are present. */
-  final int flags;
-
-  static final int FLAG_STATIC = 1;
-  static final int FLAG_ABSTRACT = FLAG_STATIC << 1;
-  static final int FLAG_FINAL = FLAG_ABSTRACT << 1;
-  static final int FLAG_VAR = FLAG_FINAL << 1;
-  static final int FLAG_CONST = FLAG_VAR << 1;
-  static final int FLAG_FACTORY = FLAG_CONST << 1;
-
-  Modifiers(NodeList nodes)
-    : this.nodes = nodes, flags = computeFlags(nodes.nodes);
-
-  Modifiers.empty() : this(new NodeList.empty());
-
-  static int computeFlags(Link<Node> nodes) {
-    int flags = 0;
-    for (; !nodes.isEmpty(); nodes = nodes.tail) {
-      String value = nodes.head.asIdentifier().source.stringValue;
-      if (value === 'static') flags += FLAG_STATIC;
-      else if (value === 'abstract') flags += FLAG_ABSTRACT;
-      else if (value === 'final') flags += FLAG_FINAL;
-      else if (value === 'var') flags += FLAG_VAR;
-      else if (value === 'const') flags += FLAG_CONST;
-      else if (value === 'factory') flags += FLAG_FACTORY;
-      else throw 'internal error: ${nodes.head}';
-    }
-    return flags;
-  }
-
-  Modifiers asModifiers() => this;
-  Token getBeginToken() => nodes.getBeginToken();
-  Token getEndToken() => nodes.getEndToken();
-  accept(Visitor visitor) => visitor.visitModifiers(this);
-  visitChildren(Visitor visitor) => nodes.accept(visitor);
-
-  bool isStatic() => (flags & FLAG_STATIC) != 0;
-  bool isAbstract() => (flags & FLAG_ABSTRACT) != 0;
-  bool isFinal() => (flags & FLAG_FINAL) != 0;
-  bool isVar() => (flags & FLAG_VAR) != 0;
-  bool isConst() => (flags & FLAG_CONST) != 0;
-  bool isFactory() => (flags & FLAG_FACTORY) != 0;
-}
-
-class StringInterpolation extends StringNode {
-  final LiteralString string;
-  final NodeList parts;
-
-  StringInterpolation(this.string, this.parts);
-
-  StringInterpolation asStringInterpolation() => this;
-
-  DartString get dartString() => null;
-  bool get isInterpolation() => true;
-
-  accept(Visitor visitor) => visitor.visitStringInterpolation(this);
-
-  visitChildren(Visitor visitor) {
-    string.accept(visitor);
-    parts.accept(visitor);
-  }
-
-  Token getBeginToken() => string.getBeginToken();
-  Token getEndToken() => parts.getEndToken();
-}
-
-class StringInterpolationPart extends Node {
-  final Expression expression;
-  final LiteralString string;
-
-  StringInterpolationPart(this.expression, this.string);
-
-  StringInterpolationPart asStringInterpolationPart() => this;
-
-  accept(Visitor visitor) => visitor.visitStringInterpolationPart(this);
-
-  visitChildren(Visitor visitor) {
-    expression.accept(visitor);
-    string.accept(visitor);
-  }
-
-  Token getBeginToken() => expression.getBeginToken();
-
-  Token getEndToken() => string.getEndToken();
-}
-
-/**
- * A class representing juxtaposed string literals.
- * The string literals can be both plain literals and string interpolations.
- */
-class StringJuxtaposition extends StringNode {
-  final Expression first;
-  final Expression second;
-
-  /**
-   * Caches the check for whether this juxtaposition contains a string
-   * interpolation
-   */
-  bool isInterpolationCache = null;
-
-  /**
-   * Caches a Dart string representation of the entire juxtaposition's
-   * content. Only juxtapositions that don't (transitively) contains
-   * interpolations have a static representation.
-   */
-  DartString dartStringCache = null;
-
-  StringJuxtaposition(this.first, this.second);
-
-  StringJuxtaposition asStringJuxtaposition() => this;
-
-  bool get isInterpolation() {
-    if (isInterpolationCache === null) {
-      isInterpolationCache = (first.accept(const IsInterpolationVisitor()) ||
-                          second.accept(const IsInterpolationVisitor()));
-    }
-    return isInterpolationCache;
-  }
-
-  /**
-   * Retrieve a single DartString that represents this entire juxtaposition
-   * of string literals.
-   * Should only be called if [isInterpolation] returns false.
-   */
-  DartString get dartString() {
-    if (isInterpolation) {
-      throw new NodeAssertionFailure(this,
-                                     "Getting dartString on interpolation;");
-    }
-    if (dartStringCache === null) {
-      DartString firstString = first.accept(const GetDartStringVisitor());
-      DartString secondString = second.accept(const GetDartStringVisitor());
-      if (firstString === null || secondString === null) {
-        return null;
-      }
-      dartStringCache = new DartString.concat(firstString, secondString);
-    }
-    return dartStringCache;
-  }
-
-  accept(Visitor visitor) => visitor.visitStringJuxtaposition(this);
-
-  void visitChildren(Visitor visitor) {
-    first.accept(visitor);
-    second.accept(visitor);
-  }
-
-  Token getBeginToken() => first.getBeginToken();
-
-  Token getEndToken() => second.getEndToken();
-}
-
-class EmptyStatement extends Statement {
-  final Token semicolonToken;
-
-  EmptyStatement(this.semicolonToken);
-
-  EmptyStatement asEmptyStatement() => this;
-
-  accept(Visitor visitor) => visitor.visitEmptyStatement(this);
-
-  visitChildren(Visitor visitor) {}
-
-  Token getBeginToken() => semicolonToken;
-
-  Token getEndToken() => semicolonToken;
-}
-
-class LiteralMap extends Expression {
-  final NodeList typeArguments;
-  final NodeList entries;
-
-  LiteralMap(this.typeArguments, this.entries);
-
-  bool isConst() => false; // TODO(ahe): Store constness.
-
-  LiteralMap asLiteralMap() => this;
-
-  accept(Visitor visitor) => visitor.visitLiteralMap(this);
-
-  visitChildren(Visitor visitor) {
-    if (typeArguments != null) typeArguments.accept(visitor);
-    entries.accept(visitor);
-  }
-
-  Token getBeginToken() => firstBeginToken(typeArguments, entries);
-
-  Token getEndToken() => entries.getEndToken();
-}
-
-class LiteralMapEntry extends Node {
-  final Expression key;
-  final Expression value;
-
-  final Token colonToken;
-
-  LiteralMapEntry(this.key, this.colonToken, this.value);
-
-  LiteralMapEntry asLiteralMapEntry() => this;
-
-  accept(Visitor visitor) => visitor.visitLiteralMapEntry(this);
-
-  visitChildren(Visitor visitor) {
-    key.accept(visitor);
-    value.accept(visitor);
-  }
-
-  Token getBeginToken() => key.getBeginToken();
-
-  Token getEndToken() => value.getEndToken();
-}
-
-class NamedArgument extends Expression {
-  final Identifier name;
-  final Expression expression;
-
-  final Token colonToken;
-
-  NamedArgument(this.name, this.colonToken, this.expression);
-
-  NamedArgument asNamedArgument() => this;
-
-  accept(Visitor visitor) => visitor.visitNamedArgument(this);
-
-  visitChildren(Visitor visitor) {
-    name.accept(visitor);
-    expression.accept(visitor);
-  }
-
-  Token getBeginToken() => name.getBeginToken();
-
-  Token getEndToken() => expression.getEndToken();
-}
-
-class SwitchStatement extends Statement {
-  final ParenthesizedExpression parenthesizedExpression;
-  final NodeList cases;
-
-  final Token switchKeyword;
-
-  SwitchStatement(this.parenthesizedExpression, this.cases,
-                  this.switchKeyword);
-
-  SwitchStatement asSwitchStatement() => this;
-
-  Expression get expression() => parenthesizedExpression.expression;
-
-  accept(Visitor visitor) => visitor.visitSwitchStatement(this);
-
-  visitChildren(Visitor visitor) {
-    parenthesizedExpression.accept(visitor);
-    cases.accept(visitor);
-  }
-
-  Token getBeginToken() => switchKeyword;
-
-  Token getEndToken() => cases.getEndToken();
-}
-
-class SwitchCase extends Node {
-  // Represents the grammar:
-  //   label? ('case' expression ':')* ('default' ':')? statement*
-  // Each expression is collected in [expressions].
-  // The 'case' keywords can be obtained using [caseKeywords()].
-  // Any actual switch case must have at least one 'case' or 'default'
-  // clause.
-  final Identifier label;
-  final NodeList expressions;
-  final Token defaultKeyword;
-  final NodeList statements;
-
-  final Token startToken;
-
-  SwitchCase(this.label, this.expressions, this.defaultKeyword,
-             this.statements, this.startToken);
-
-  SwitchCase asSwitchCase() => this;
-
-  bool get isDefaultCase() => defaultKeyword !== null;
-
-  accept(Visitor visitor) => visitor.visitSwitchCase(this);
-
-  visitChildren(Visitor visitor) {
-    if (label !== null) label.accept(visitor);
-    expressions.accept(visitor);
-    statements.accept(visitor);
-  }
-
-  Token getBeginToken() {
-    return startToken;
-  }
-
-  Token getEndToken() {
-    if (statements.nodes.isEmpty()) {
-      // All cases must have at least one expression or be the default.
-      if (defaultKeyword !== null) {
-        // The colon after 'default'.
-        return defaultKeyword.next;
-      }
-      // The colon after the expression.
-      return expressions.getEndToken().next;
-    } else {
-      return statements.getEndToken();
-    }
-  }
-
-  Link<Token> caseKeywords() {
-    Token token = startToken;
-    if (label !== null) {
-      // Skip past the label: <Identifier> ':'.
-      token = token.next.next;
-    }
-    Link<Token> recursiveGetCases(Token token, Link<Expression> expressions) {
-      if (token.stringValue === 'case') {
-        Token colon = expressions.head.getEndToken().next;
-        return new Link<Token>(token,
-                               recursiveGetCases(colon.next, expressions.tail));
-      }
-      return const EmptyLink<Token>();
-    }
-    return recursiveGetCases(token, expressions);
-  }
-}
-
-class GotoStatement extends Statement {
-  final Identifier target;
-  final Token keywordToken;
-  final Token semicolonToken;
-
-  GotoStatement(this.target, this.keywordToken, this.semicolonToken);
-
-  visitChildren(Visitor visitor) {
-    if (target !== null) target.accept(visitor);
-  }
-
-  Token getBeginToken() => keywordToken;
-
-  Token getEndToken() => semicolonToken;
-
-  // TODO(ahe): make class abstract instead of adding an abstract method.
-  abstract accept(Visitor visitor);
-}
-
-class BreakStatement extends GotoStatement {
-  BreakStatement(Identifier target, Token keywordToken, Token semicolonToken)
-    : super(target, keywordToken, semicolonToken);
-
-  BreakStatement asBreakStatement() => this;
-
-  accept(Visitor visitor) => visitor.visitBreakStatement(this);
-}
-
-class ContinueStatement extends GotoStatement {
-  ContinueStatement(Identifier target, Token keywordToken, Token semicolonToken)
-    : super(target, keywordToken, semicolonToken);
-
-  ContinueStatement asContinueStatement() => this;
-
-  accept(Visitor visitor) => visitor.visitContinueStatement(this);
-}
-
-class ForInStatement extends Loop {
-  final Node declaredIdentifier;
-  final Expression expression;
-
-  final Token forToken;
-  final Token inToken;
-
-  ForInStatement(this.declaredIdentifier, this.expression,
-                 Statement body, this.forToken, this.inToken) : super(body);
-
-  Expression get condition() => null;
-
-  ForInStatement asForInStatement() => this;
-
-  accept(Visitor visitor) => visitor.visitForInStatement(this);
-
-  visitChildren(Visitor visitor) {
-    declaredIdentifier.accept(visitor);
-    expression.accept(visitor);
-    body.accept(visitor);
-  }
-
-  Token getBeginToken() => forToken;
-
-  Token getEndToken() => body.getEndToken();
-}
-
-class LabeledStatement extends Statement {
-  final Identifier label;
-  final Token colonToken;
-  final Statement statement;
-
-  LabeledStatement(this.label, this.colonToken, this.statement);
-
-  LabeledStatement asLabeledStatement() => this;
-
-  accept(Visitor visitor) => visitor.visitLabeledStatement(this);
-
-  visitChildren(Visitor visitor) {
-    label.accept(visitor);
-    statement.accept(visitor);
-  }
-
-  Token getBeginToken() => label.getBeginToken();
-
-  Token getEndToken() => statement.getEndToken();
-
-  bool isValidContinueTarget() => statement.isValidContinueTarget();
-
-  Node getBody() {
-    if (statement is! LabeledStatement) return statement;
-    LabeledStatement labeled = statement;
-    return labeled.getBody();
-  }
-}
-
-class ScriptTag extends Node {
-  final Identifier tag;
-  final StringNode argument;
-  final Identifier prefixIdentifier;
-  final StringNode prefix;
-
-  final Token beginToken;
-  final Token endToken;
-
-  ScriptTag(this.tag, this.argument, this.prefixIdentifier, this.prefix,
-            this.beginToken, this.endToken);
-
-  bool isImport() => tag.source == const SourceString("import");
-  bool isSource() => tag.source == const SourceString("source");
-  bool isLibrary() => tag.source == const SourceString("library");
-  bool isResource() => tag.source == const SourceString("resource");
-
-  ScriptTag asScriptTag() => this;
-
-  accept(Visitor visitor) => visitor.visitScriptTag(this);
-
-  visitChildren(Visitor visitor) {
-    tag.accept(visitor);
-    argument.accept(visitor);
-    if (prefixIdentifier !== null) prefixIdentifier.accept(visitor);
-    if (prefix !== null) prefix.accept(visitor);
-  }
-
-  Token getBeginToken() => beginToken;
-
-  Token getEndToken() => endToken;
-}
-
-class Typedef extends Node {
-  final TypeAnnotation returnType;
-  final Identifier name;
-  final NodeList typeParameters;
-  final NodeList formals;
-
-  final Token typedefKeyword;
-  final Token endToken;
-
-  Typedef(this.returnType, this.name, this.typeParameters, this.formals,
-          this.typedefKeyword, this.endToken);
-
-  Typedef asTypedef() => this;
-
-  accept(Visitor visitor) => visitor.visitTypedef(this);
-
-  visitChildren(Visitor visitor) {
-    if (returnType !== null) returnType.accept(visitor);
-    name.accept(visitor);
-    if (typeParameters !== null) typeParameters.accept(visitor);
-    formals.accept(visitor);
-  }
-
-  Token getBeginToken() => typedefKeyword;
-
-  Token getEndToken() => endToken;
-}
-
-class TryStatement extends Statement {
-  final Block tryBlock;
-  final NodeList catchBlocks;
-  final Block finallyBlock;
-
-  final Token tryKeyword;
-  final Token finallyKeyword;
-
-  TryStatement(this.tryBlock, this.catchBlocks, this.finallyBlock,
-               this.tryKeyword, this.finallyKeyword);
-
-  TryStatement asTryStatement() => this;
-
-  accept(Visitor visitor) => visitor.visitTryStatement(this);
-
-  visitChildren(Visitor visitor) {
-    tryBlock.accept(visitor);
-    catchBlocks.accept(visitor);
-    if (finallyBlock !== null) finallyBlock.accept(visitor);
-  }
-
-  Token getBeginToken() => tryKeyword;
-
-  Token getEndToken() {
-    if (finallyBlock !== null) return finallyBlock.getEndToken();
-    if (!catchBlocks.isEmpty()) return catchBlocks.getEndToken();
-    return tryBlock.getEndToken();
-  }
-}
-
-class CatchBlock extends Node {
-  final NodeList formals;
-  final Block block;
-
-  final catchKeyword;
-
-  CatchBlock(this.formals, this.block, this.catchKeyword);
-
-  CatchBlock asCatchBlock() => this;
-
-  accept(Visitor visitor) => visitor.visitCatchBlock(this);
-
-  Node get exception() {
-    if (formals.nodes.isEmpty()) return null;
-    VariableDefinitions declarations = formals.nodes.head;
-    return declarations.definitions.nodes.head;
-  }
-
-  Node get trace() {
-    if (formals.nodes.isEmpty()) return null;
-    Link<Node> declarations = formals.nodes.tail;
-    if (declarations.isEmpty()) return null;
-    VariableDefinitions head = declarations.head;
-    return head.definitions.nodes.head;
-  }
-
-  visitChildren(Visitor visitor) {
-    formals.accept(visitor);
-    block.accept(visitor);
-  }
-
-  Token getBeginToken() => catchKeyword;
-
-  Token getEndToken() => block.getEndToken();
-}
-
-class Initializers {
-  static bool isSuperConstructorCall(Send node) {
-    return (node.receiver === null &&
-            node.selector.asIdentifier() !== null &&
-            node.selector.asIdentifier().isSuper()) ||
-           (node.receiver !== null &&
-            node.receiver.asIdentifier() !== null &&
-            node.receiver.asIdentifier().isSuper() &&
-            node.selector.asIdentifier() !== null);
-  }
-
-  static bool isConstructorRedirect(Send node) {
-    return (node.receiver === null &&
-            node.selector.asIdentifier() !== null &&
-            node.selector.asIdentifier().isThis()) ||
-           (node.receiver !== null &&
-            node.receiver.asIdentifier() !== null &&
-            node.receiver.asIdentifier().isThis() &&
-            node.selector.asIdentifier() !== null);
-  }
-}
-
-class GetDartStringVisitor extends AbstractVisitor<DartString> {
-  const GetDartStringVisitor();
-  DartString visitNode(Node node) => null;
-  DartString visitStringJuxtaposition(StringJuxtaposition node)
-      => node.dartString;
-  DartString visitLiteralString(LiteralString node) => node.dartString;
-}
-
-class IsInterpolationVisitor extends AbstractVisitor<bool> {
-  const IsInterpolationVisitor();
-  bool visitNode(Node node) => false;
-  bool visitStringInterpolation(StringInterpolation node) => true;
-  bool visitStringJuxtaposition(StringJuxtaposition node)
-      => node.isInterpolation;
-}
-
-/**
- * If the given node is a send set, it visits its initializer (first
- * argument).
- *
- * TODO(ahe): This method is controversial, the team needs to discuss
- * if top-level methods are acceptable and what naming conventions to
- * use.
- */
-initializerDo(Node node, f(Node node)) {
-  SendSet send = node.asSendSet();
-  if (send !== null) return f(send.arguments.head);
-}