Support parameter metadata.

sdk/lib/_internal/compiler/implementation/tree/nodes.dart

 // 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.
 
 part of tree;
 
 abstract class Visitor<R> {
   const Visitor();
 
   R visitNode(Node node);
@@ skipping 30 matching lines @@
   R visitLiteralBool(LiteralBool node) => visitLiteral(node);
   R visitLiteralDouble(LiteralDouble node) => visitLiteral(node);
   R visitLiteralInt(LiteralInt node) => visitLiteral(node);
   R visitLiteralList(LiteralList node) => visitExpression(node);
   R visitLiteralMap(LiteralMap node) => visitExpression(node);
   R visitLiteralMapEntry(LiteralMapEntry node) => visitNode(node);
   R visitLiteralNull(LiteralNull node) => visitLiteral(node);
   R visitLiteralString(LiteralString node) => visitStringNode(node);
   R visitStringJuxtaposition(StringJuxtaposition node) => visitStringNode(node);
   R visitLoop(Loop node) => visitStatement(node);
+  R visitMetadata(Metadata node) => visitNode(node);
   R visitMixinApplication(MixinApplication node) => visitNode(node);
   R visitModifiers(Modifiers node) => visitNode(node);
   R visitNamedArgument(NamedArgument node) => visitExpression(node);
   R visitNamedMixinApplication(NamedMixinApplication node) {
     return visitMixinApplication(node);
   }
   R visitNewExpression(NewExpression node) => visitExpression(node);
   R visitNodeList(NodeList node) => visitNode(node);
   R visitOperator(Operator node) => visitIdentifier(node);
   R visitParenthesizedExpression(ParenthesizedExpression node) {
@@ skipping 105 matching lines @@
   LibraryDependency asLibraryDependency() => 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;
   LiteralSymbol asLiteralSymbol() => null;
+  Metadata asMetadata() => null;
   MixinApplication asMixinApplication() => null;
   Modifiers asModifiers() => null;
   NamedArgument asNamedArgument() => null;
   NamedMixinApplication asNamedMixinApplication() => null;
   NewExpression asNewExpression() => null;
   NodeList asNodeList() => null;
   Operator asOperator() => null;
   ParenthesizedExpression asParenthesizedExpression() => null;
   Part asPart() => null;
   PartOf asPartOf() => null;
@@ skipping 286 matching lines @@
     return super.getBeginToken();
   }
 
   Token getEndToken() {
     if (isPostfix) return assignmentOperator.getEndToken();
     return super.getEndToken();
   }
 }
 
 class NewExpression extends Expression {
-  /** The token NEW or CONST */
+  /** The token NEW or CONST or `null` for metadata */
   final Token newToken;
 
   // Note: we expect that send.receiver is null.
   final Send send;
 
   NewExpression([this.newToken, this.send]);
 
   NewExpression asNewExpression() => this;
 
   accept(Visitor visitor) => visitor.visitNewExpression(this);
 
   visitChildren(Visitor visitor) {
     if (send != null) send.accept(visitor);
   }
 
   bool isConst() {
-    return identical(newToken.stringValue, 'const')
-        || identical(newToken.stringValue, '@');
+    return newToken == null || identical(newToken.stringValue, 'const');
   }
 
-  Token getBeginToken() => newToken;
+  Token getBeginToken() => newToken != null ? newToken : send.getBeginToken();
 
   Token getEndToken() => send.getEndToken();
 }
 
 class NodeList extends Node {
   final Link<Node> nodes;
   final Token beginToken;
   final Token endToken;
   final String delimiter;
   bool get isEmpty => nodes.isEmpty;
@@ skipping 615 matching lines @@
   TypeVariable asTypeVariable() => this;
 
   Token getBeginToken() => name.getBeginToken();
 
   Token getEndToken() {
     return (bound != null) ? bound.getEndToken() : name.getEndToken();
   }
 }
 
 class VariableDefinitions extends Statement {
+  final NodeList metadata;
   final TypeAnnotation type;
   final Modifiers modifiers;
   final NodeList definitions;
-  VariableDefinitions(this.type, this.modifiers, this.definitions) {
+
+  VariableDefinitions(this.type,
+                      this.modifiers,
+                      this.definitions)
+      : this.metadata = null {
     assert(modifiers != null);
   }
 
+  // TODO(johnniwinther): Make this its own node type.
+  VariableDefinitions.forParameter(this.metadata,
+                                   this.type,
+                                   this.modifiers,
+                                   this.definitions) {
+    assert(modifiers != null);
+  }
+
   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() {
@@ skipping 885 matching lines @@
     if (type != null) type.accept(visitor);
     if (formals != null) formals.accept(visitor);
     block.accept(visitor);
   }
 
   Token getBeginToken() => onKeyword != null ? onKeyword : catchKeyword;
 
   Token getEndToken() => block.getEndToken();
 }
 
+class Metadata extends Node {
+  final Token token;
+  final Expression expression;
+
+  Metadata(this.token, this.expression);
+
+  Metadata asMetadata() => this;
+
+  accept(Visitor visitor) => visitor.visitMetadata(this);
+
+  visitChildren(Visitor visitor) {
+    expression.accept(visitor);
+  }
+
+  Token getBeginToken() => token;
+
+  Token getEndToken() => expression.getEndToken();
+}
+
 class Initializers {
   static bool isSuperConstructorCall(Send node) {
     return (node.receiver == null && node.selector.isSuper()) ||
            (node.receiver != null &&
             node.receiver.isSuper() &&
             node.selector.asIdentifier() != null);
   }
 
   static bool isConstructorRedirect(Send node) {
     return (node.receiver == null && node.selector.isThis()) ||
@@ skipping 24 matching lines @@
  * 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);
 }