Update charted to 0.4.8 and roll

packages/quiver/lib/src/iterables/generating_iterable.dart

 // Copyright 2014 Google Inc. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 part of quiver.iterables;
 
+typedef T _Initial<T>();
+typedef T _Next<T>(T value);
+
 Iterable generate(initial(), next(o)) => new GeneratingIterable(initial, next);
 
-/**
- * An Iterable who's first value is [object] and who's subsequent values are
- * generated by passing the current value to the [next] function.
- *
- * The class is useful for creating lazy iterables from object hierarchies and
- * graphs.
- *
- * It's important that for the given initial value and next function that the
- * sequence of items eventually terminates. Otherwise calling methods that
- * expect a finite sequence, like `length` or `last`, will cause an infinite
- * loop.
- *
- * Example:
- *
- *     class Node {
- *       Node parent;
- *
- *       /**
- *        * An iterable of node and all ancestors up to the root.
- *        */
- *       Iterable<Node> ancestors =
- *           new GeneratingIterable<Node>(() => this, (n) => n.parent);
- *
- *       /**
- *        * An iterable of the root and the path of nodes to this. The reverse
- *        * of ancestors.
- *        */
- *       Iterable<Node> path = ancestors.toList().reversed();
- *     }
- *
- */
+/// An Iterable who's first value is [object] and who's subsequent values are
+/// generated by passing the current value to the [next] function.
+///
+/// The class is useful for creating lazy iterables from object hierarchies and
+/// graphs.
+///
+/// It's important that for the given initial value and next function that the
+/// sequence of items eventually terminates. Otherwise calling methods that
+/// expect a finite sequence, like `length` or `last`, will cause an infinite
+/// loop.
+///
+/// Example:
+///
+///     class Node {
+///       Node parent;
+///
+///       /// An iterable of node and all ancestors up to the root.
+///       Iterable<Node> ancestors =
+///           new GeneratingIterable<Node>(() => this, (n) => n.parent);
+///
+///       /// An iterable of the root and the path of nodes to this. The
+///       /// reverse of ancestors.
+///       Iterable<Node> path = ancestors.toList().reversed();
+///     }
 class GeneratingIterable<T> extends IterableBase<T> {
-  final initial;
-  final next;
+  final _Initial<T> initial;
+  final _Next<T> next;
 
-  GeneratingIterable(T this.initial(), T this.next(T o));
+  GeneratingIterable(this.initial, this.next);
 
   @override
   Iterator<T> get iterator => new _GeneratingIterator(initial(), next);
 }
 
 class _GeneratingIterator<T> implements Iterator<T> {
-  final next;
+  final _Next<T> next;
   T object;
   bool started = false;
 
-  _GeneratingIterator(T this.object, T this.next(T o));
+  _GeneratingIterator(T this.object, this.next);
 
   @override
   T get current => started ? object : null;
 
   @override
   bool moveNext() {
     if (object == null) return false;
     if (started) {
       object = next(object);
     } else {
       started = true;
     }
     return object != null;
   }
 }