anchor.diff:    Watch _watch;
   
     static final RegExp IS_WHEN = new RegExp(r'^when-(minus-)?.');
  +
     static const Map<String, Symbol> SYMBOLS = const {
         'zero'  : #zero,
         'one'   : #one,
  
positive.code:     }
    }
  
  
    void _setAndWatch(template) {
      if (_watch != null) _watch.remove();
      var expression = _expressionCache.putIfAbsent(template, () =>
  
negative.code:       'other' : #other,
    };
  
    NgPluralize(this._scope, this._element, this._interpolate, this._filters) {
      var attrs = _element.attributes;
      final whens = attrs['when'] == null
          ? <String, String>{}
          : _scope.eval(attrs['when']);
      _offset = attrs['offset'] == null ? 0 : int.parse(attrs['offset']);
  
      _element.attributes.keys.where((k) => IS_WHEN.hasMatch(k)).forEach((k) {
        var ruleName = k
  