CODEWITHSUNDEEP
scalaapache-spark
Becca
Becca

Reputation: 189

How do I access a nested function in a scala object

I'm trying to access a nested function. I am able to access func1 but I'm running into issues when trying to access func2.

//attempting to call methods in different class

val t1 = test
t1.func1()
t1.func1(df).func2("test")

object test {
    def func1 (df: dataframe): tt = {

      def func2 (ab: String): String =  {
        // do something
      } else {
        // do nothing
      }

      def func3 (ab2: String): String = {
        //do something
      } else {
        // do nothing
      }

    }

  val t1 = test
  t1.func1()
  t1.func1(df).func2("test")

I'm expecting to access func2 without any errors

Upvotes: 0

Views: 1910

Answers (2)

klswt
klswt

Reputation: 39

The closure property prevents captured identifiers to be accessed from outside the enclosed scope. Using an object or class instead of a function and overloading apply appropriately would make the inner scope accessible. 

object test {

    case class func1(df: dataframe){

        def apply(..)= {..}

        def func2 (ab: String): String =  {..}
        def func3 (ab2: String): String = {..}
   }
}

Upvotes: 3

Jonathan Myers
Jonathan Myers

Reputation: 930

You can consider func2 to be the equivalent of a nested variable. You aren't able to access this outside of its parent function.

Try changing a few things around to make this example more obvious:

object test {
    def func1 (df: dataframe): String = {
        val data = "hi"
        "bye"
    }
}
val t1 = test
t1.func1(df).data

Would you expect to be able to access data here?

If you try to make a reference to func2 outside of func1, you will receive a compiler error.

If you need access to func2 and don't have any other constraints, I'd recommend defining it outside the scope of func1.

Upvotes: 4

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