Custom Operator to accept Record as input

I really liked the Json Rules Engine. It would be good if record object is also pushed as input to operator so that one can compare relative value from the same Record using Json Path by introducing custom Operator in the engine. At present, there is not way to have Record object as operator input.

未指定文件或测试。首先定位自定义操作符的求值路径，以及其当前输入的构造方式。完成的标准是：自定义操作符可以接收 Record 对象，并通过 Json Path 比较同一记录中的值，同时为该行为提供覆盖。

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