Support for observable models, fixes #259

example/todomvc/model.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.
 
 library model;
 
+import 'package:web_ui/observe.dart';
+import 'package:web_ui/observe/html.dart';
+
+@observable
 class ViewModel {
   bool isVisible(Todo todo) => todo != null &&
       ((showIncomplete && !todo.done) || (showDone && todo.done));
 
-  bool showIncomplete = true;
+  bool get showIncomplete => locationHash != '#/completed';
 
-  bool showDone = true;
+  bool get showDone => locationHash != '#/active';
 }
 
 final ViewModel viewModel = new ViewModel();
 
 // The real model:
 
+@observable
 class AppModel {
-  List<Todo> todos = <Todo>[];
+  ObservableList<Todo> todos = new ObservableList<Todo>();
 
   // TODO(jmesserly): remove this once List has a remove method.
   void removeTodo(Todo todo) {
     var index = todos.indexOf(todo);
     if (index != -1) {
       todos.removeRange(index, 1);
     }
   }
 
   bool get allChecked => todos.length > 0 && todos.every((t) => t.done);
 
   set allChecked(bool value) => todos.forEach((t) { t.done = value; });
 
   int get doneCount {
     int res = 0;
     todos.forEach((t) { if (t.done) res++; });
     return res;
   }
 
   int get remaining => todos.length - doneCount;
 
   void clearDone() {
-    todos = todos.where((t) => !t.done).toList();
+    // TODO(jmesserly): should methods on ObservableList return Observables?
+    todos = toObservable(todos.where((t) => !t.done));
   }
 }
 
 final AppModel app = new AppModel();
 
+@observable
 class Todo {
   String task;
   bool done = false;
 
   Todo(this.task);
 
   String toString() => "$task ${done ? '(done)' : '(not done)'}";
 }