Convert String and List to abstract classes.

lib/core/collection.dart

Index: lib/core/collection.dart
diff --git a/lib/core/collection.dart b/lib/core/collection.dart
index ffad48d6c76913e76bb79efee8548fc3708b6b72..27336d831e9c6f816f2f72047b12ca5720d17163 100644
--- a/lib/core/collection.dart
+++ b/lib/core/collection.dart
@@ -32,8 +32,8 @@ abstract class Collection<E> extends Iterable<E> {
    *
    *   collection.reduce(0, (prev, element) => prev + element);
    */
-  Dynamic reduce(Dynamic initialValue,
-                 Dynamic combine(Dynamic previousValue, E element));
+  Dynamic reduce(var initialValue,

[srdjan, 2012/09/28 17:52:22]

Why not remove Dynamic everywhere?

[Lasse Reichstein Nielsen, 2012/09/30 20:46:43]

"var" is not a valid return type, and I don't like not writing a return type
(looks like an omission).

[srdjan, 2012/10/02 17:21:14]

This is not the the style that has been used by most people in Dart team
(checked with Ivan and Bob). It is important that we have a unified style in the
libraries.I.e., rather than "Dynamic foo(var a, var b)", we should write "foo(a,
b)"

+                 Dynamic combine(var previousValue, E element));
 
   /**
    * Returns a new collection with the elements of this collection