frog: allow optional arguments in implicit method closures.

frog/gen.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.
 
 /**
  * Top level generator object for writing code and keeping track of
  * dependencies.
  *
  * Should have two compilation models, but only one implemented so far.
  *
@@ skipping 957 matching lines @@
       }
     }
 
     if (usesBind) world.gen.corejs.ensureBind();
   }
 
   static bool _maybeGenerateBoundGetter(MethodMember m, CodeWriter defWriter) {
     if (m._provideGetter) {
       String suffix = world.gen._writePrototypePatch(m.declaringType,
           'get\$${m.jsname}', 'function() {', defWriter, false);
-      defWriter.writeln('return this.${m.jsname}.bind(this);');
+      if (m.parameters.some((p) => p.isOptional)) {
+        defWriter.writeln('var \$bound = this.${m.jsname}.bind(this);');

[sra1, 2012/04/21 03:33:14]

nit.
$bound could be any name (e.g. 'f') since there are no free vars here.
no need for $.

+        defWriter.writeln('\$bound.\$optional = this.${m.jsname}.\$optional;');
+        defWriter.writeln('return \$bound;');
+      } else {
+        defWriter.writeln('return this.${m.jsname}.bind(this);');
+      }
       defWriter.exitBlock(suffix);
       return true;
     }
     return false;
   }
 
   /**
    * Generates information about the default/named arguments into the JS code.
    * Only methods that are passed as bound methods to "var" need this. It is
    * generated to support run time stub creation.
@@ skipping 1541 matching lines @@
     return true;
   }
 
 }
 
 class ReturnKind {
   static final int IGNORE = 1;
   static final int POST = 2;
   static final int PRE = 3;
 }