Move toString() to collection classes.

sdk/lib/_collection_dev/iterable.dart

Index: sdk/lib/_collection_dev/iterable.dart
diff --git a/sdk/lib/_collection_dev/iterable.dart b/sdk/lib/_collection_dev/iterable.dart
index 6e1e5ecb7c1b79be349de5fd215359d8294a6b0e..29e23289b30837e5160a080d6905ffa444da0ed7 100644
--- a/sdk/lib/_collection_dev/iterable.dart
+++ b/sdk/lib/_collection_dev/iterable.dart
@@ -702,6 +702,9 @@ abstract class BidirectionalIterator<T> implements Iterator<T> {
  * The uses of this class will be replaced by mixins.
  */
 class IterableMixinWorkaround {
+  // A list to identify cyclic collections during toString() calls. 
+  static List _toStringList = new List();
+  
   static bool contains(Iterable iterable, var element) {
     for (final e in iterable) {
       if (e == element) return true;
@@ -895,6 +898,53 @@ class IterableMixinWorkaround {
     return buffer.toString();
   }
 
+  static String toStringIterable(Iterable iterable) {
+    for (int i = 0; i < _toStringList.length; i++) {
+      if (identical(_toStringList[i], iterable)) { return '{...}'; }
+    }
+    
+    var result = new StringBuffer();

[floitsch, 2013/07/08 16:12:34]

Type variable.

[zarah, 2013/07/08 16:57:46]

Done.

+    try {
+      _toStringList.add(iterable);
+      result.write('{');
+      bool first = true;
+      for (var e in iterable) {

[floitsch, 2013/07/08 16:12:34]

You could see, if iterable.join(", ") doesn't cost too much.

[zarah, 2013/07/08 16:57:46]

Use writeAll instead since it is cheaper.

+        if (!first) {
+          result.write(', ');
+        }
+        first = false;
+        result.write(e);
+      }
+      result.write('}');
+    } finally {

[floitsch, 2013/07/08 16:12:34]

assert that you are the last.

[zarah, 2013/07/08 16:57:46]

Done.

+      _toStringList.removeLast();
+    }
+    return result.toString();      
+  }
+  
+  static String toStringList(List list) {
+    for (int i = 0; i < _toStringList.length; i++) {
+      if (identical(_toStringList[i], list)) { return '[...]'; }
+    }
+
+    var result = new StringBuffer();
+    try {
+      _toStringList.add(list);
+      result.write('[');
+      for (int i = 0; i < list.length; i++) {

[floitsch, 2013/07/08 16:12:34]

ditto. If list.join(", ") isn't too expensive it would remove code duplication.

[zarah, 2013/07/08 16:57:46]

Use writeAll instead since it is cheaper.

+        if (i > 0) {
+          result.write(', ');
+        }
+        result.write(list[i]);
+      }
+      result.write(']');
+     } finally {
+        _toStringList.removeLast();  
+     }
+     
+    return result.toString();
+  }
+
   static Iterable where(Iterable iterable, bool f(var element)) {
     return new WhereIterable(iterable, f);
   }