fold

inline fun <C> fold(ifLeft: (A) -> C, ifRight: (B) -> C): C

Applies ifLeft if this is a Left or ifRight if this is a Right.

Example:

import arrow.core.*

fun main() {
  fun possiblyFailingOperation(): Either.Right<Int> =
    Either.Right(1)
  //sampleStart
  val result: Either<Exception, Int> = possiblyFailingOperation()
  result.fold(
       { println("operation failed with $it") },
       { println("operation succeeded with $it") }
  )
  //sampleEnd
}

Return

the results of applying the function

Parameters

ifLeft

the function to apply if this is a Left

ifRight

the function to apply if this is a Right