Better parsing of interfaces.

dart/frog/leg/scanner/parser.dart

 // Copyright (c) 2011, 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.
 
 /**
  * An event generating parser of Dart programs. This parser expects
  * all tokens in a linked list.
  */
 class Parser {
   final Listener listener;
   bool mayParseFunctionExpressions = true;
 
   Parser(Listener this.listener);
 
   void parseUnit(Token token) {
     while (token.kind !== EOF_TOKEN) {
-      final String value = token.stringValue;
-      if (value === 'interface') {
-        token = parseInterface(token);
-      } else if ((value === 'abstract') || (value === 'class')) {
-        token = parseClass(token);
-      } else if (value === 'typedef') {
-        token = parseNamedFunctionAlias(token);
-      } else if (value === '#') {
-        token = parseScriptTags(token);
-      } else {
-        token = parseTopLevelMember(token);
-      }
+      token = parseTopLevelDeclaration(token);
     }
   }
 
+  Token parseTopLevelDeclaration(Token token) {
+    final String value = token.stringValue;
+    if (value === 'interface') {
+      return parseInterface(token);
+    } else if ((value === 'abstract') || (value === 'class')) {
+      return parseClass(token);
+    } else if (value === 'typedef') {
+      return parseNamedFunctionAlias(token);
+    } else if (value === '#') {
+      return parseScriptTags(token);
+    } else {
+      return parseTopLevelMember(token);
+    }
+  }
+
   Token parseInterface(Token token) {
     Token interfaceKeyword = token;
     listener.beginInterface(token);
     token = parseIdentifier(token.next);
     token = parseTypeVariablesOpt(token);
     int supertypeCount = 0;
     Token extendsKeyword = null;
     if (optional('extends', token)) {
       extendsKeyword = token;
       do {
@@ skipping 1578 matching lines @@
     }
     listener.handleContinueStatement(hasTarget, continueKeyword, token);
     return expectSemicolon(token);
   }
 
   Token parseEmptyStatement(Token token) {
     listener.handleEmptyStatement(token);
     return expectSemicolon(token);
   }
 }