huaxingao commented on pull request #33803: URL: https://github.com/apache/spark/pull/33803#issuecomment-910928285
I was planning to add `references` to `interface Expression`, but I changed my mind. 1. I am not sure if every `Expression` needs a `references`. Right now `Transform` and `Filter` need this `references`, but I don't think all the `Expression` need this `references` method. For example, I don't think the aggregates such as `Min` or `Max` need this `references`. These aggregates only have a single column. Of course, we can still implement `references` and return this single column, but i don't think these will be used any where. 2. for the `references()` in Filter, I think we are OK. Since we only support `FieldReference` in filter now, just return it if it's a `FieldReference`, otherwise return an empty array. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
