Fasta parser listener infrastructure.

pkg/fasta/lib/src/source/diet_parser.dart

Index: pkg/fasta/lib/src/source/diet_parser.dart
diff --git a/pkg/fasta/lib/src/source/diet_parser.dart b/pkg/fasta/lib/src/source/diet_parser.dart
new file mode 100644
index 0000000000000000000000000000000000000000..1811f859f1e8f60b2c7f996b130e28be8d59b0d2
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+++ b/pkg/fasta/lib/src/source/diet_parser.dart
@@ -0,0 +1,47 @@
+// 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.
+
+library fasta.diet_parser;
+
+import 'package:dart_scanner/src/token.dart' show
+    BeginGroupToken,
+    Token;
+
+import 'package:dart_parser/src/class_member_parser.dart' show
+    ClassMemberParser;
+
+import 'package:dart_parser/src/error_kind.dart' show
+    ErrorKind;
+
+import 'package:dart_parser/src/listener.dart' show
+    Listener;
+
+import 'package:dart_parser/src/parser.dart' show
+    optional;
+
+// TODO(ahe): Move this to parser package.
+class DietParser extends ClassMemberParser {
+  DietParser(Listener listener,
+      {bool asyncAwaitKeywordsEnabled: false,
+       bool enableGenericMethodSyntax: false})
+      : super(listener, asyncAwaitKeywordsEnabled: asyncAwaitKeywordsEnabled,
+          enableGenericMethodSyntax: enableGenericMethodSyntax);
+
+  Token parseFormalParameters(Token token) => skipFormals(token);
+
+  Token skipFormals(Token token) {
+    listener.beginOptionalFormalParameters(token);
+    if (!optional('(', token)) {
+      if (optional(';', token)) {
+        listener.reportError(token, ErrorKind.EXPECTED_OPEN_PARENS);
+        return token;
+      }
+      return listener.unexpected(token);
+    }
+    BeginGroupToken beginGroupToken = token;
+    Token endToken = beginGroupToken.endGroup;
+    listener.endFormalParameters(0, token, endToken);
+    return endToken.next;
+  }
+}