Attach source range information to parsed YAML nodes.

pkg/yaml/lib/src/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 yaml.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) => new _DeepEquals().equals(obj1, obj2);
-
-/// A class that provides access to the list of parent objects used for loop
-/// detection.
-class _DeepEquals {
-  final _parents1 = [];
-  final _parents2 = [];
-
-  /// Returns whether [obj1] and [obj2] are structurally equivalent.
-  bool equals(obj1, obj2) {
-    // _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);
-      } else if (obj1 is Map && obj2 is Map) {
-        return _mapEquals(obj1, obj2);
-      } else if (obj1 is num && obj2 is num) {
-        return _numEquals(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) {
-    if (list1.length != list2.length) return false;
-
-    for (var i = 0; i < list1.length; i++) {
-      if (!equals(list1[i], list2[i])) return false;
-    }
-
-    return true;
-  }
-
-  /// Returns whether [map1] and [map2] are structurally equal. 
-  bool _mapEquals(Map map1, Map map2) {
-    if (map1.length != map2.length) return false;
-
-    for (var key in map1.keys) {
-      if (!map2.containsKey(key)) return false;
-      if (!equals(map1[key], map2[key])) return false;
-    }
-
-    return true;
-  }
-
-  /// Returns whether two numbers are equivalent.
-  ///
-  /// This differs from `n1 == n2` in that it considers `NaN` to be equal to
-  /// itself.
-  bool _numEquals(num n1, num n2) {
-    if (n1.isNaN && n2.isNaN) return true;
-    return n1 == n2;
-  }
-}