Restructure YAML package suitable for pub lish

utils/pub/yaml/deep_equals.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 deep_equals;
-
-/// Returns whether two objects are structurally equivalent. This considers NaN
-/// values to be equivalent. It also handles self-referential structures.
-bool deepEquals(obj1, obj2, [List parents1, List parents2]) {
-  if (identical(obj1, obj2)) return true;
-  if (parents1 == null) {
-    parents1 = [];
-    parents2 = [];
-  }
-
-  // parents1 and parents2 are guaranteed to be the same size.
-  for (var i = 0; i < parents1.length; i++) {
-    var loop1 = identical(obj1, parents1[i]);
-    var loop2 = identical(obj2, parents2[i]);
-    // If both structures loop in the same place, they're equal at that point in
-    // the structure. If one loops and the other doesn't, they're not equal.
-    if (loop1 && loop2) return true;
-    if (loop1 || loop2) return false;
-  }
-
-  parents1.add(obj1);
-  parents2.add(obj2);
-  try {
-    if (obj1 is List && obj2 is List) {
-      return _listEquals(obj1, obj2, parents1, parents2);
-    } else if (obj1 is Map && obj2 is Map) {
-      return _mapEquals(obj1, obj2, parents1, parents2);
-    } else if (obj1 is double && obj2 is double) {
-      return _doubleEquals(obj1, obj2);
-    } else {
-      return obj1 == obj2;
-    }
-  } finally {
-    parents1.removeLast();
-    parents2.removeLast();
-  }
-}
-
-/// Returns whether [list1] and [list2] are structurally equal. 
-bool _listEquals(List list1, List list2, List parents1, List parents2) {
-  if (list1.length != list2.length) return false;
-
-  for (var i = 0; i < list1.length; i++) {
-    if (!deepEquals(list1[i], list2[i], parents1, parents2)) return false;
-  }
-
-  return true;
-}
-
-/// Returns whether [map1] and [map2] are structurally equal. 
-bool _mapEquals(Map map1, Map map2, List parents1, List parents2) {
-  if (map1.length != map2.length) return false;
-
-  for (var key in map1.keys) {
-    if (!map2.containsKey(key)) return false;
-    if (!deepEquals(map1[key], map2[key], parents1, parents2)) return false;
-  }
-
-  return true;
-}
-
-/// Returns whether two doubles are equivalent. This differs from `d1 == d2` in
-/// that it considers NaN to be equal to itself.
-bool _doubleEquals(double d1, double d2) {
-  if (d1.isNaN && d2.isNaN) return true;
-  return d1 == d2;
-}