First stab at parsing redirecting constructors.

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.
@@ skipping 898 matching lines @@
     token = token.next; // Skip 'factory'.
     token = parseIdentifier(token);
     token = parseQualifiedRestOpt(token);
     token = parseTypeVariablesOpt(token);
     Token period = null;
     if (optional('.', token)) {
       period = token;
       token = parseIdentifier(token.next);
     }
     token = parseFormalParameters(token);
-    token = parseFunctionBody(token, false);
+    if (optional('=', token)) {
+      token = parseRedirectingFactoryBody(token);
+    } else {
+      token = parseFunctionBody(token, false);
+    }
     listener.endFactoryMethod(start, period, token);
     return token.next;
   }
 
   Token parseOperatorName(Token token) {
     assert(optional('operator', token));
     if (isUserDefinableOperator(token.next.stringValue)) {
       Token operator = token;
       token = token.next;
       listener.handleOperatorName(operator, token);
@@ skipping 54 matching lines @@
     token = parseIdentifier(token);
     listener.endFunctionName(token);
     token = parseFormalParameters(token);
     listener.handleNoInitializers();
     bool isBlock = optional('{', token);
     token = parseFunctionBody(token, true);
     listener.endFunction(null, token);
     return isBlock ? token.next : token;
   }
 
+  Token parseRedirectingFactoryBody(Token token) {
+    listener.beginRedirectingFactoryBody(token);
+    assert('=' === token.stringValue);

[ahe, 2012/10/05 08:23:20]

assert(optional('=', token));

I should clean up the other uses similar to this.

[Lasse Reichstein Nielsen, 2012/10/09 09:46:54]

Done.

+    Token equals = token;
+    token = parseType(token.next);
+    Token dot = null;
+    if (optional('.', token)) {
+      dot = token;
+      token = parseIdentifier(token.next);
+    }
+    expectSemicolon(token);
+    listener.endRedirectingFactoryBody(equals, dot, token);
+    return token;

[ahe, 2012/10/05 08:23:20]

You should consume the semicolon token if you require it.

[Lasse Reichstein Nielsen, 2012/10/09 09:46:54]

I don't think that's compatible with parseFunctionBody.
In parseFunctionBody, the semicolon is not consumed, and the calling methods use
the returned token (the semicolon) as the end-token of their calls to
endFunction. The parseRedirectingFactoryBody method is used in the same place as
a call to parseFunctionBody, and seems to need the same behavior.

+  }
+
   Token parseFunctionBody(Token token, bool isExpression) {
     if (optional(';', token)) {
       listener.endFunctionBody(0, null, token);
       return token;
     } else if (optional('=>', token)) {
       Token begin = token;
       token = parseExpression(token.next);
       if (!isExpression) {
         expectSemicolon(token);
         listener.endReturnStatement(true, begin, token);
@@ skipping 1041 matching lines @@
     }
     listener.handleContinueStatement(hasTarget, continueKeyword, token);
     return expectSemicolon(token);
   }
 
   Token parseEmptyStatement(Token token) {
     listener.handleEmptyStatement(token);
     return expectSemicolon(token);
   }
 }