Parse metadata, but ignore it.

dart/lib/compiler/implementation/scanner/parser.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.
 
 /**
  * An event generating parser of Dart programs. This parser expects
  * all tokens in a linked list (aka a token stream).
  *
  * The class [Scanner] is used to generate a token stream. See the
  * file scanner.dart.
  *
  * Subclasses of the class [Listener] are used to listen to events.
  */
 class Parser {
   final Listener listener;
   bool mayParseFunctionExpressions = true;
 
   Parser(Listener this.listener);
 
   void parseUnit(Token token) {
     while (token.kind !== EOF_TOKEN) {
       token = parseTopLevelDeclaration(token);
     }
   }
 
   Token parseTopLevelDeclaration(Token token) {
+    token = parseMetadataStar(token);

[ngeoffray, 2012/08/21 06:28:31]

What's the Star suffix for? for consistency, shouldn't it be parseMetadataOpt?

[Johnni Winther, 2012/08/21 07:05:31]

Star means 0 or more. Opt means 0 or 1.

[ahe, 2012/08/21 07:07:10]

The suffix "star" refers to the asterisk in grammar rules:

metadata*

The suffix "opt" refers to the question mark in grammar rules:

metadata: qualified arguments?

Often I have been able to use:

parseFoo and parseFoos

But parseMetadatas doesn't sound right.

[ahe, 2012/08/21 10:49:46]

I have updated the class comment.

     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 parseMetadataStar(Token token) {
+    while (optional('@', token)) {
+      token = parseMetadata(token);
+    }
+    return token;
+  }
+
+  Token parseMetadata(Token token) {
+    listener.beginMetadata(token);
+    Token atToken = token;
+    assert(optional('@', token));
+    token = parseIdentifier(token.next);
+    token = parseQualifiedRestOpt(token);
+    token = parseArgumentsOpt(token);
+    listener.endMetadata(atToken, token);
+    return 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 528 matching lines @@
       final Token peek = peekAfterExpectedType(token);
       if (isGetOrSet(peek) && isIdentifier(peek.next)) {
         // type? get identifier
         return peek;
       }
     }
     return null;
   }
 
   Token parseMember(Token token) {
+    token = parseMetadataStar(token);
     String value = token.stringValue;
     if (value === 'factory' ||
         (value === 'external' && optional('factory', token.next))) {
       return parseFactoryMethod(token);
     }
     Token start = token;
     listener.beginMember(token);
     token = parseModifiers(token);
     Token getOrSet = findGetOrSet(token);
     if (token === getOrSet) token = token.next;
@@ skipping 1190 matching lines @@
     }
     listener.handleContinueStatement(hasTarget, continueKeyword, token);
     return expectSemicolon(token);
   }
 
   Token parseEmptyStatement(Token token) {
     listener.handleEmptyStatement(token);
     return expectSemicolon(token);
   }
 }