private static IFilterSpecification GetBinaryOperation(FilterOperator op, IFilterSpecification left, IFilterSpecification right) => new FilterSpecification { LeftSpecification = left, Operator = op, RightSpecification = right };
private static IFilterSpecification GetCondition(FilterCondition condition, IFilterSpecification left, IFilterSpecification right) => new FilterConditionSpecification { Condition = condition, LeftSpecification = left, RightSpecification = right };
private static IEnumerable <DslQueryParameter> GetParameters(IFilterSpecification specification) => specification == null ? Enumerable.Empty <DslQueryParameter>() : specification.GetParameters();