Why is RDD to PairRDDFunctions only via implicits?

[Justin Pihony]

This ticket <https://issues.apache.org/jira/browse/SPARK-4397> improved the
RDD API, but it could be even more discoverable if made available via the
API directly. I assume this was originally an omission that now needs to be
kept for backwards compatibility, but would any of the repo owners be open
to making this more discoverable to the point of API docs and tab
completion (while keeping both binary and source compatibility)?


    class PairRDD extends RDD{
      ....pair methods
    }

    RDD{
      def map[K: ClassTag, V: ClassTag](f: T => (K,V)):PairRDD[K,V]
    }

As long as the implicits remain, then compatibility remains, but now it is
explicit in the docs on how to get a PairRDD and in tab completion.

Thoughts?

Justin Pihony