public override Expression HandleOperation(
            QueryableFilterContext context,
            IFilterOperationField field,
            IValueNode value,
            object parsedValue)
        {
            Expression property = context.GetInstance();

            return(FilterExpressionBuilder.Equals(property, parsedValue));
        }
        public static FilterScope <Expression> AddIsNullClosure(
            this QueryableFilterContext context)
        {
            var closure = new QueryableScope(
                context.RuntimeTypes.Peek(), "_s" + context.Scopes.Count, false);

            context.Scopes.Push(closure);

            context.GetLevel().Enqueue(
                FilterExpressionBuilder.Equals(context.GetClosure().Parameter, null));

            return(closure);
        }